The United States entered into World War I in April 1917, more than two and a half years after the war began in Europe.
Apart from an Anglophile element urging early support for the British and an anti-tsarist element sympathizing with Germany's war against Russia, American public opinion had generally reflected a desire to stay out of the war: the sentiment for neutrality was particularly strong among Irish Americans, German Americans, and Scandinavian Americans,  as well as among church leaders and women in general. On the other hand, even before World War I had broken out, American opinion had been overall more negative toward the German Empire than toward any other country in Europe.  Over time, especially after reports of German atrocities in Belgium in 1914 and following the sinking of the passenger liner RMS Lusitania in 1915, Americans increasingly came to see Germany as the aggressor in Europe.
While the country was at peace, American banks made huge loans to the Entente powers, which were used mainly to buy munitions, raw materials, and food from across the Atlantic. Although Woodrow Wilson made minimal preparations for a land war before 1917, he did authorize a ship-building program for the United States Navy. The president was narrowly re-elected in 1916 on an anti-war platform.
By 1917, with Belgium and Northern France occupied, with Russia experiencing political upheaval, and with the remaining Entente nations low on credit, Germany appeared to have the upper hand in Europe.  However, a British economic embargo and naval blockade was causing severe shortages of fuel and food in Germany. Berlin then decided to resume unrestricted submarine warfare. The aim was to break the transatlantic supply chain to Britain from other nations, although the German high command realized that sinking American-flagged ships would almost certainly bring the United States into the war.
Germany also made a secret offer to help Mexico regain territories lost in the Mexican–American War in an encoded telegram known as the Zimmermann Telegram, which was intercepted by British intelligence. Publication of that communique outraged Americans just as German submarines started sinking American merchant ships in the North Atlantic. Wilson then asked Congress for "a war to end all wars" that would "make the world safe for democracy", and Congress voted to declare war on Germany on April 6, 1917.  U.S. troops began major combat operations on the Western Front under General John J. Pershing in the summer of 1918.
Britain used its large navy to prevent cargo vessels entering German ports, mainly by intercepting them in the North Sea between the coasts of Scotland and Norway. The wider sea approaches to Britain and France, their distance from German harbors and the significantly smaller size of the German surface fleet all made it effectively impossible for Germany to proportionally reciprocate using conventional naval methods. Instead, Germany used submarines to sink merchant ships heading for Entente ports.
The Royal Navy successfully stopped the shipment of most war supplies and food to Germany. Neutral American ships that tried to trade with Germany were seized or turned back by the Royal Navy who viewed such trade as in direct conflict with the Allies' war efforts.  The impact from the blockade became apparent very slowly because Germany and its allies controlled extensive farmlands and raw materials. It was eventually successful because Germany and Austria-Hungary had decimated their agricultural production by taking so many farmers into their armies. The turnip winter of 1916–17 already showed severe shortages. By 1918, German cities were on the verge of a major food shortage; the front-line soldiers were on short rations and were running out of essential supplies. 
Germany also considered a blockade. "England wants to starve us", said Admiral Alfred von Tirpitz, the man who built the German fleet and who remained a key advisor to the Kaiser Wilhelm II. "We can play the same game. We can bottle her up and destroy every ship that endeavors to break the blockade".  Unable to challenge the more powerful Royal Navy on the surface, Tirpitz wanted to scare off merchant and passenger ships en route to Britain. He reasoned that since the island of Britain depended on imports of food, raw materials, and manufactured goods, scaring off a substantial number of the ships would effectively undercut its long-term ability to maintain an army on the Western Front. While Germany had only nine long-range U-boats at the start of the war, it had ample shipyard capacity to build the hundreds needed. However, the United States demanded that Germany respect the international agreements upon "freedom of the seas", which protected neutral American ships on the high seas from seizure or sinking by either belligerent. Furthermore, Americans insisted that causing the deaths of innocent American civilians was unwarranted and grounds for a declaration of war.  The Royal Navy frequently violated America's neutral rights by seizing merchant ships. Wilson's top advisor, Colonel Edward M. House commented that, "The British have gone as far as they possibly could in violating neutral rights, though they have done it in the most courteous way".  When Wilson protested these violations of American neutrality, the Royal Navy backed down.
German submarines torpedoed ships without warning, causing sailors and passengers to drown. Berlin explained that submarines were so vulnerable that they dared not surface near merchant ships that might be carrying guns and which were too small to rescue submarine crews. Britain armed most of its merchant ships with medium caliber guns that could sink a submarine, making above-water attacks too risky. In February 1915, the United States warned Germany about the misuse of submarines. On April 22, the German Imperial Embassy warned U.S. citizens against boarding vessels to Britain, which would have to face German attack. On May 7, Germany torpedoed the British passenger liner RMS Lusitania, sinking her. This act of aggression caused the loss of 1,198 civilian lives, including 128 Americans. The sinking of a large, unarmed passenger ship, combined with the previous stories of atrocities in Belgium, shocked Americans and turned public opinion hostile to Germany, although not yet to the point of war.  Wilson issued a warning to Germany that it would face "strict accountability" if it sank more neutral U.S. passenger ships.  Berlin acquiesced, ordering its submarines to avoid passenger ships.
By January 1917, however, Field Marshal Paul von Hindenburg and General Erich Ludendorff decided that an unrestricted submarine blockade was the only way to achieve a decisive victory. They demanded that Kaiser Wilhelm order unrestricted submarine warfare be resumed. Germany knew this decision meant war with the United States, but they gambled that they could win before America's potential strength could be mobilized.  However, they overestimated how many ships they could sink and thus the extent Britain would be weakened. Finally, they did not foresee that convoys could and would be used to defeat their efforts. They believed that the United States was so weak militarily that it could not be a factor on the Western Front for more than a year. The civilian government in Berlin objected, but the Kaiser sided with his military. 
The beginning of war in Europe coincided with the end of the Recession of 1913–1914 in America. Exports to belligerent nations rose rapidly over the first four years of the War from $824.8 million in 1913 to $2.25 billion in 1917.  Loans from American financial institutions to the Allied nations in Europe also increased dramatically over the same period.  Economic activity towards the end of this period boomed as government resources aided the production of the private sector. Between 1914 and 1917, industrial production increased 32% and GNP increased by almost 20%.  The improvements to industrial production in the United States outlasted the war. The capital build-up that had allowed American companies to supply belligerents and the American army resulted in a greater long-run rate of production even after the war had ended in 1918. 
The J.P. Morgan Bank offered assistance in the wartime financing of Britain and France from the earliest stages of the conflict through America's entrance in 1917. J.P. Morgan's New York office, was designated as the primary financial agent to the British government starting in 1914 after successful lobbying by the British ambassador, Sir Cecil Spring Rice.  The same bank would later take a similar role in France. J.P. Morgan & Co. became the primary issuer of loans to the French government, providing the capital of American investors,  operating from their French affiliate Morgan, Harjes.  Relations between Morgan and the French government became tense as the war raged on with no end in sight however.  France's ability to borrow from other sources diminished, leading to greater lending rates and a depressing of the value of the franc. After the war ended, J.P. Morgan & Co. continued to aid the French government financially through monetary stabilization and debt relief. 
Because America was still a declared neutral state, the financial dealings of American banks in Europe caused a great deal of contention between Wall Street and the U.S. government. Secretary of State William Jennings Bryan strictly opposed financial support of warring nations and wanted to ban loans to the belligerents in August 1914.  He told President Wilson that "refusal to loan to any belligerent would naturally tend to hasten a conclusion of the war." Wilson at first agreed, but then reversed himself when France argued that if it was legal to buy American goods then it was legal to take out credits on the purchase. 
J.P. Morgan issued loans to France including one in March 1915 and, following negotiations with the Anglo-French Financial Commission, another joint loan to Britain and France in October 1915, the latter amounting to US$500,000,000.  Although the stance of the U.S. government was that stopping such financial assistance could hasten the end of the war and therefore save lives, little was done to insure adherence to the ban on loans, in part due to pressure from Allied governments and American business interests. 
The American steel industry had faced difficulties and declining profits during the Recession of 1913–1914.  As war began in Europe, however, the increased demand for tools of war began a period of heightened productivity that alleviated many U.S. industrial companies from the low-growth environment of the recession. Bethlehem Steel took particular advantage of the increased demand for armaments abroad. Prior to American entrance into the war, these companies benefit from unrestricted commerce with sovereign customers abroad. After President Wilson issued his declaration of war, the companies were subjected to price controls created by the U.S. Trade Commission in order to insure that the U.S. military would have access to the necessary armaments. 
By the end of the war in 1918, Bethlehem Steel had produced 65,000 pounds of forged military products and 70 million pounds of armor plate, 1.1 billion pounds of steel for shells, and 20.1 million rounds of artillery ammunition for Britain and France.  Bethlehem Steel took advantage of the domestic armaments market and produced 60% of the American weaponry and 40% of the artillery shells used in the war.  Even with price controls and a lower profit margin on manufactured goods, the profits resulting from wartime sales expanded the company into the third largest manufacturing company in the country. Bethlehem Steel became the primary arms supplier for the United States and other allied powers again in 1939. 
Historians divide the views of American political, social and business leaders into four distinct groupings—the camps were mostly informal:
The first of these were the Non-Interventionists, a loosely affiliated and politically diverse anti-war movement which sought to keep the United States out of the conflict altogether. Members of this group tended to view the war as a clash between the imperialist and militaristic great powers of Europe, whom they deemed to be corrupt and unworthy of support. Others were pacifists, who objected on moral grounds. Prominent leaders included Democrats like former Secretary of State William Jennings Bryan, industrialist Henry Ford and publisher William Randolph Hearst; Republicans like Senator Robert M. La Follette of Wisconsin and Senator George W. Norris of Nebraska; and Progressive activist Jane Addams.
At the far-left end of the political spectrum, the Socialists, led by their perennial candidate for President, Eugene V. Debs, and movement veterans like Victor L. Berger and Morris Hillquit, were staunch anti-militarists. They were opposed to any US intervention, branding the conflict as a "capitalist war" that American workers should resist. However, after the US joined the war in April 1917, a schism developed between the anti-war party leadership and a pro-war faction of socialist writers and intellectuals led by John Spargo, William English Walling and E. Haldeman-Julius. This clique founded the rival Social Democratic League of America to promote the war effort among their fellow Socialists. 
Next were the more moderate Liberal-Internationalists. This bipartisan group reluctantly supported American entry into the war against Germany, with the postwar goal of establishing strong international institutions designed to peacefully resolve future conflicts between nations and to promote liberal democratic values more broadly. This faction's views were advocated by interest groups such as the League to Enforce Peace. Adherents included US President Woodrow Wilson, his influential advisor Edward M. House, former President William Howard Taft, businessman and philanthropist Edward Filene, Wall Street financier Bernard Baruch and Harvard University President Abbott Lawrence Lowell. 
Finally, there were the Atlanticists. Unambiguously pro-Allied, this group had championed American intervention in the war since the sinking of the Lusitania and also strongly supported the Preparedness Movement. Proponents also advocated for an enduring postwar alliance with Great Britain, which they saw as vital to maintaining America's future security. Prominent among the Anglophile Eastern establishment, supporters included, former President Theodore Roosevelt, Major General Leonard Wood, lawyer and diplomat Joseph Hodges Choate, former Secretary of War Henry Stimson, Manhattan attorney Paul D. Cravath and Senators Henry Cabot Lodge of Massachusetts and Elihu Root of New York. 
A surprising factor in the development of American public opinion was how little the political parties became involved. Wilson and the Democrats in 1916 campaigned on the slogan "He kept us out of war!", saying a Republican victory would mean war with both Mexico and Germany. His position probably was critical in winning the Western states.  Charles Evans Hughes, the GOP candidate, insisted on downplaying the war issue. 
The Socialist Party of America talked peace. Socialist rhetoric declared the European conflict to be "an imperialist war" blaming the war on capitalism and pledged total opposition. "A bayonet", its propaganda said, "was a weapon with a worker at each end".  When war was declared, however, many Socialists, including much of the party's intellectual leadership, supported the decision and sided with the pro-Allied efforts. The majority, led by Eugene V. Debs (the party's presidential candidate from 1900 to 1912), remained ideological and die-hard opponents.   Many socialists came under investigation from the Espionage Act of 1917 and many suspected of treason were arrested, including Debs . This would only increase the Socialists' and anti-war groups' resentment toward the American government. 
The working class was relatively quiet and tended to divide along ethnic lines. At the beginning of the war, neither working men nor farmers took a large interest in the debates on war preparation.    Samuel Gompers, head of the AFL labor movement, denounced the war in 1914 as "unnatural, unjustified, and unholy", but by 1916 he was supporting Wilson's limited preparedness program, against the objections of Socialist union activists. In 1916 the labor unions supported Wilson on domestic issues and ignored the war question. 
The war at first disrupted the cotton market; the Royal Navy blockaded shipments to Germany, and prices fell from 11 cents a pound to only 4 cents. By 1916, however, the British decided to bolster the price to 10 cents to avoid losing Southern support. The cotton growers seem to have moved from neutrality to intervention at about the same pace as the rest of the nation.   Midwestern farmers generally opposed the war, especially those of German and Scandinavian descent. The Midwest became the stronghold of isolationism; other remote rural areas also saw no need for war. 
The African-American community did not take a strong position one way or the other. A month after Congress declared war, W. E. B. Du Bois called on African-Americans to "fight shoulder to shoulder with the world to gain a world where war shall be no more".  Once the war began and black men were drafted, they worked to achieve equality.  Many had hoped the community's help in the war efforts abroad would earn civil rights at home. When such civil liberties were still not granted, many African-Americans grew tired of waiting for recognition of their rights as American citizens. 
There was a strong antiwar element among poor rural whites in the South and border states.  In rural Missouri for example, distrust of powerful Eastern influences focused on the risk that Wall Street would lead America into war.  Across the South poor white farmers warned each other that "a rich man's war meant a poor man's fight," and they wanted nothing of it.   Antiwar sentiment was strongest among Christians affiliated with the Churches of Christ, the Holiness movement and Pentecostal churches.  Congressman James Hay, Democrat of Virginia was the powerful chairman of the House Committee on Military Affairs. He repeatedly blocked prewar efforts to modernize and enlarge the army. Preparedness was not needed because Americans were already safe, he insisted in January 1915:
Educated, urban, middle-class southerners generally supported entering the war, and many worked on mobilization committees. In contrast to this many rural southern whites opposed entering the war.  Those with more formal education were more in favor of entering the war and those in the south with less formal education were more likely to oppose entering the war. Letters to newspapers with spelling or grammatical errors were overwhelmingly letters which opposed entry into the war, whereas letters with no spelling or grammatical errors were overwhelming those which supported entry into the war.  When the war began Texas and Georgia led the southern states with volunteers. 1,404 from Texas, 1,397 from Georgia, 538 from Louisiana, 532 from Tennessee, 470 from Alabama, 353 from North Carolina, 316 from Florida, and 225 from South Carolina.  Every southern Senator voted in favor of entering the war except for Mississippi firebrand James K. Vardaman.  By coincidence, there were some regions of the south which were more heavily in favor of intervention than others. Georgia provided the most volunteers per capita out of any state in the union before conscription and had the highest portion of pro-British newspapers before America's entry into the war. There were five competing newspapers which covered the region of Southeast Georgia, all of whom were outspokenly Anglophilic during the decades preceding the war, and during the early phases of the war. All five of which also highlighted German atrocities during the rape of Belgium and the murder of Edith Cavell. Other magazines with nationwide distribution which were pro-British such as The Outlook and The Literary Digest had a disproportionately high distribution throughout every region of the state of Georgia as well as the region of northern Alabama in the area around Huntsville and Decatur (when the war began there were 470 volunteers from the state of Alabama, of these, over 400 came from Huntsville-Decatur region).    Support for American entry into the war was also pronounced in central Tennessee. Letters to newspapers which expressed pro-British, anti-German or pro-interventionist sentiment were common. In between October 1914 and April 1917, letters about the war to newspapers from Tennessee included at least one of these three sentiments. In the Tennessee counties of Cheatham County, Robertson County, Sumner County, Wilson County, Rutherford County, Williamson County, Maury County, Marshall County, Bedford County, Coffee Couny and Cannon County over half of the letters contained all three of these elements.  In South Carolina there was support for America entering the war. Led by Governor Richard I. Manning, the cities of Greenville, Spartanburg, and Columbia had started lobbying for army training centers in their communities, for both economic and patriotic reasons, in preparation for American entry into the war. Similarly, Charleston had interned a German freighter in 1914, and when the freighter's skeleton crew tried to block Charleston harbor they were all arrested and imprisoned. From that point on Charleston was buzzing with "war fever." 1915, 1916 and early 1917 were all years when Charleston and the low country coastal counties to the south of Charleston, were all gripped by sentiment that was very "pro-British and anti-German."   
German Americans by this time usually had only weak ties to Germany; however, they were fearful of negative treatment they might receive if the United States entered the war (such mistreatment was already happening to German-descent citizens in Canada and Australia). Almost none called for intervening on Germany's side, instead calling for neutrality and speaking of the superiority of German culture. As more nations were drawn into the conflict, however, the English-languages press increasingly supporting Britain, while the German-American media called for neutrality while also defending Germany's position. Chicago's Germans worked to secure a complete embargo on all arms shipments to Europe. In 1916, large crowds in Chicago's Germania celebrated the Kaiser's birthday, something they had not done before the war.  German Americans in early 1917 still called for neutrality, but proclaimed that if a war came they would be loyal to the United States. By this point, they had been excluded almost entirely from national discourse on the subject.  German-American Socialists in Milwaukee, Wisconsin actively campaigned against entry into the war. 
Leaders of most religious groups (except the Episcopalians) tended to pacifism, as did leaders of the woman's movement. The Methodists and Quakers among others were vocal opponents of the war.  President Wilson, who was a devout Presbyterian, would often frame the war in terms of good and evil in an appeal for religious support of the war. 
A concerted effort was made by pacifists including Jane Addams, Oswald Garrison Villard, David Starr Jordan, Henry Ford, Lillian Wald, and Carrie Chapman Catt. Their goal was to encourage Wilson's efforts to mediate an end of the war by bringing the belligerents to the conference table.  Finally in 1917 Wilson convinced some of them that to be truly anti-war they needed to support what he promised would be "a war to end all wars". 
Once war was declared, the more liberal denominations, which had endorsed the Social Gospel, called for a war for righteousness that would help uplift all mankind. The theme—an aspect of American exceptionalism—was that God had chosen America as his tool to bring redemption to the world. 
American Catholic bishops maintained a general silence toward the issue of intervention. Millions of Catholics lived in both warring camps, and Catholic Americans tended to split on ethnic lines in their opinions toward American involvement in the war. At the time, heavily Catholic towns and cities in the East and Midwest often contained multiple parishes, each serving a single ethnic group, such as Irish, German, Italian, Polish, or English. American Catholics of Irish and German descent opposed intervention most strongly. Pope Benedict XV made several attempts to negotiate a peace. All of his efforts were rebuffed by both the Allies and the Germans, and throughout the war the Vatican maintained a policy of strict neutrality.
In 1914–1916, there were few Jewish Americans in favor of American entry into the war.[ citation needed ] New York City, with its Jewish community numbering 1.5 million, was a center of antiwar activism, much of which was organized by labor unions which were primarily on the political left and therefore opposed to a war that they viewed to be a battle between several great powers.  
Some Jewish communities worked together during the war years to provide relief to Jewish communities in Eastern Europe which were decimated by fighting, famine and scorched earth policies of the Russian and Austro-German armies.  
Of greatest concern to Jewish Americans was the Tsarist government in Russia due its toleration of pogroms and allegedly following antisemitic policies. As historian Joseph Rappaport reported through his study of Yiddish press during the war, "The pro-Germanism of America's immigrant Jews was an inevitable consequence of their Russophobia."  However, after the February Revolution of 1917 led to transformation of Russia into republic, a major obstacle was removed for those Jews who refused to support American entry into the war on the side of Russia.  The draft went smoothly in New York City, and left-wing opposition to the war largely collapsed when Zionists saw the possibility of using the war to demand a state of Israel. 
The most effective domestic opponents of the war were Irish-American Catholics. Many had little interest in the continent; despite traditional hostility towards the United Kingdom and British Empire, some Irish Americans took a more neutral stance on the issue of aiding the entente on account of the recently passed Government of Ireland Act 1914, allowing Irish Home Rule. However, the Act was suspended until the war ended. John Redmond and the Irish Parliamentary Party (IPP) declared that Irish Volunteers should support America's pro-Allied war efforts first; his political opponents argued that it was not the time to support Britain in its attempt to "strengthen and expand her empire".  The attacks on the IPP and pro-Allied press showed a firm belief that a German victory would hasten the achievement of an independent Irish state. Yet rather than proposing intervention on behalf of the Germans, Irish American leaders and organizations focused on demanding American neutrality. But the increased contact between militant Irish nationalists and German agents in the United States only fueled concerns of where the primary loyalties of Irish Americans lay.  Nevertheless, close to 1,000 Irish-born Americans died fighting with the U.S. armed forces in WWI.  The Easter Rising in Dublin in April 1916 was defeated within a week and its leaders executed by firing squad. Both the mainstream Irish and American press treated the uprising as foolish and misguided, with later joining the British press in suspecting it was largely created and planned by the Germans. Overall public opinion remained faithfully pro-Entente. 
In many major American cities, Irish-Americans dominated the Democratic party, forcing Wilson to take into account their political viewpoints. Irish-American political efforts influenced the United States into defining its own objectives from the war separate from those of its allies, which were primarily (among other objectives) self-determination for the various nations and ethnic groups of Europe. Wilson gave assurances he would promote Irish independence after the war which helped to secure support for his war policies. However once the war was over Wilson reneged, disappointing many Irish-Americans.  Though a ideological proponent of self-determination in general, Wilson saw the Irish situation purely as an internal affair of the United Kingdom and did not perceive the dispute and the unrest in Ireland as one in the same as that being faced by the various other nationalities in Europe as a fall-out from World War I. 
Some British immigrants worked actively for intervention. London-born Samuel Insull, Chicago's leading industrialist, for example, enthusiastically provided money, propaganda, and means for volunteers to enter the British or Canadian armies. After the United States' entry, Insull directed the Illinois State Council of Defense, with responsibility for organizing the state's mobilization. 
Immigrants from eastern Europe usually cared more about politics in their homeland than politics in the United States. Spokesmen for Slavic immigrants hoped that an Allied victory would bring independence for their homelands.  Large numbers of Hungarian immigrants who were liberal and nationalist in sentiment, and sought an independent Hungary, separate from the Austro-Hungarian Empire lobbied in favor of the war and allied themselves with the Atlanticist or Anglophile portion of the population. This community was largely pro-British and anti-German in sentiment.    Albanian-Americans in communities such as Boston also campaigned for entry into the war and were overwhelmingly pro-British and anti-German, as well as hopeful the war would lead to an independent Albania which would be free from the Ottoman Empire.  The state of Wisconsin had the distinction of being the most isolationist state due to the large numbers of German-Americans, socialists, pacifists and others present in the state, however, the exception to this were pockets within the state such as the city of Green Bay. Green Bay had a large number of pro-Allied immigrants, including the largest Belgian immigrant community in the entire country, and for this reason anti-German sentiment and pro-war sentiment were both significantly higher in Green Bay than in the country as a whole.  There was a large Serbian-American community in Alaska which also was enthusiastically in favor of American entry into World War I. In the case of Alaska, which was at the time a territory, thousands of Serbian immigrants and Serbian-Americans volunteered early to join the United States Army shortly after the declaration of war, after the community had been outspokenly in favor of America's entry into the war before this. During the First World War, many Serbian Americans volunteered to fight overseas, with thousands coming from Alaska.  
Henry Ford supported the pacifist cause by sponsoring a large-scale private peace mission, with numerous activists and intellectuals aboard the "Peace Ship' (the ocean liner Oscar II). Ford chartered the ship in 1915 and invited prominent peace activists to join him to meet with leaders on both sides in Europe. He hoped to create enough publicity to prompt the belligerent nations to convene a peace conference and mediate an end to the war. The mission was widely mocked by the press, which wrote about the "Ship of Fools." Infighting between the activists, mockery by the press contingent aboard, and an outbreak of influenza marred the voyage. Four days after the ship arrived in neutral Norway, a beleaguered and physically ill Ford abandoned the mission and returned to the United States; he had demonstrated that independent small efforts accomplished nothing. 
On July 24, 1915, the German embassy's commercial attaché, Heinrich Albert, left his briefcase on a train in New York City, where an alert Secret Service agent, Frank Burke, snatched it up.  Wilson let the newspapers publish the contents, which indicated a systematic effort by Berlin to subsidize friendly newspapers and block British purchases of war materials. Berlin's top espionage agent, debonnaire Franz Rintelen von Kleist was spending millions to finance sabotage in Canada, stir up trouble between the United States and Mexico and to incite labor strikes.  Germany took the blame as Americans grew ever more worried about the vulnerability of a free society to subversion. Indeed, one of the main fears Americans of all stations had in 1916–1919 was that spies and saboteurs were everywhere. This sentiment played a major role in arousing fear of Germany, and suspicions regarding everyone of German descent who could not "prove" 100% loyalty. 
By 1915, Americans were paying much more attention to the war. The sinking of the Lusitania had a strong effect on public opinion because of the deaths of American civilians. That year, a strong "Preparedness" movement emerged.  Proponents argued that the United States needed to immediately build up strong naval and land forces for defensive purposes; an unspoken assumption was that America would fight sooner or later. General Leonard Wood (still on active duty after serving a term as Chief of Staff of the Army), former president Theodore Roosevelt, and former secretaries of war Elihu Root and Henry Stimson were the driving forces behind Preparedness, along with many of the nation's most prominent bankers, industrialists, lawyers and scions of prominent families. Indeed, there emerged an "Atlanticist" foreign policy establishment, a group of influential Americans drawn primarily from upper-class lawyers, bankers, academics, and politicians of the Northeast, committed to a strand of Anglophile internationalism. Representative was Paul D. Cravath, one of New York's foremost corporation lawyers. For Cravath, in his mid-fifties when the war began, the conflict served as an epiphany, sparking an interest in international affairs that dominated his remaining career. Fiercely Anglophile, he strongly supported American intervention in the war and hoped that close Anglo-American cooperation would be the guiding principle of postwar international organization. 
The Preparedness movement had a "realistic" philosophy of world affairs—they believed that economic strength and military muscle were more decisive than idealistic crusades focused on causes like democracy and national self-determination. Emphasizing over and over the weak state of national defenses, they showed that America's 100,000-man Army even augmented by the 112,000 National Guardsmen, was outnumbered 20 to one by Germany's army, which was drawn from a smaller population. Similarly in 1915, the armed forces of Britain and her Empire  ), France, Russia, Austria-Hungary, Ottoman Empire, Italy, Bulgaria, Romania, Serbia, Belgium, Japan and Greece were all larger and more experienced than the United States military, in many cases significantly so. 
Reform to them meant UMT or "universal military training". They proposed a national service program under which the 600,000 men who turned 18 every year would be required to spend six months in military training, and afterwards be assigned to reserve units. The small regular army would primarily be a training agency.
Antimilitarists complained the plan would make America resemble Germany (which required two years' active duty). Advocates retorted that military "service" was an essential duty of citizenship, and that without the commonality provided by such service the nation would splinter into antagonistic ethnic groups. One spokesman promised that UMT would become "a real melting pot, under which the fire is hot enough to fuse the elements into one common mass of Americanism". Furthermore, they promised, the discipline and training would make for a better paid work force. Hostility to military service was strong at the time, and the program failed to win approval. In World War II, when Stimson as Secretary of War proposed a similar program of universal peacetime service, he was defeated. 
Underscoring its commitment, the Preparedness movement set up and funded its own summer training camps at Plattsburgh, New York, and other sites, where 40,000 college alumni became physically fit, learned to march and shoot, and ultimately provided the cadre of a wartime officer corps.  Suggestions by labor unions that talented working-class youth be invited to Plattsburgh were ignored. The Preparedness movement was distant not only from the working classes but also from the middle-class leadership of most of small-town America. It had had little use for the National Guard, which it saw as politicized, localistic, poorly armed, ill trained, too inclined to idealistic crusading (as against Spain in 1898), and too lacking in understanding of world affairs. The National Guard on the other hand was securely rooted in state and local politics, with representation from a very broad cross section of American society. The Guard was one of the nation's few institutions that (in some northern states) accepted blacks on an equal footing.
The Democratic party saw the Preparedness movement as a threat. Roosevelt, Root and Wood were prospective Republican presidential candidates. More subtly, the Democrats were rooted in localism that appreciated the National Guard, and the voters were hostile to the rich and powerful in the first place. Working with the Democrats who controlled Congress, Wilson was able to sidetrack the Preparedness forces. Army and Navy leaders were forced to testify before Congress to the effect that the nation's military was in excellent shape.
In fact, neither the Army nor Navy was in shape for war. The Navy had fine ships but Wilson had been using them to threaten Mexico, and the fleet's readiness had suffered. The crews of the Texas and the New York , the two newest and largest battleships, had never fired a gun, and the morale of the sailors was low. In addition, it was outnumbered and outgunned when compared to the British and German navies. The Army and Navy air forces were tiny in size. Despite the flood of new weapons systems created by the British, Germans, French, Austro-Hungarians, Italians, and others in the war in Europe, the Army was paying scant attention. For example, it was making no studies of trench warfare, poison gas, heavy artillery, or tanks and was utterly unfamiliar with the rapid evolution of aerial warfare. The Democrats in Congress tried to cut the military budget in 1915. The Preparedness movement effectively exploited the surge of outrage over the Lusitania in May 1915, forcing the Democrats to promise some improvements to the military and naval forces. Wilson, less fearful of the Navy, embraced a long-term building program designed to make the fleet the equal of the Royal Navy by the mid-1920s, although this would not be achieved until World War II. "Realism" was at work here; the admirals were Mahanians and they therefore wanted a surface fleet of heavy battleships second to none—that is, equal to Britain. The facts of submarine warfare (which necessitated destroyers, not battleships) and the possibilities of imminent war with Germany (or with Britain, for that matter), were simply ignored.
Wilson's program for the Army touched off a firestorm.  Secretary of War Lindley Garrison adopted many of the proposals of the Preparedness leaders, especially their emphasis on a large federal reserve and abandonment of the National Guard. Garrison's proposals not only outraged the localistic politicians of both parties, they also offended a strongly held belief shared by the liberal wing of the Progressive movement. They felt that warfare always had a hidden economic motivation. Specifically, they warned the chief warmongers were New York bankers (like J. P. Morgan) with millions at risk, profiteering munition makers (like Bethlehem Steel, which made armor, and DuPont, which made powder) and unspecified industrialists searching for global markets to control. Antiwar critics blasted them. These special interests were too powerful, especially, Senator La Follette noted, in the conservative wing of the Republican Party. The only road to peace was disarmament, reiterated Bryan.
Garrison's plan unleashed the fiercest battle in peacetime history over the relationship of military planning to national goals.  In peacetime, War Department arsenals and Navy yards manufactured nearly all munitions that lacked civilian uses, including warships, artillery, naval guns, and shells. Items available on the civilian market, such as food, horses, saddles, wagons, and uniforms were always purchased from civilian contractors. Armor plate (and after 1918, airplanes) was an exception that has caused unremitting controversy for a century. After World War II, the arsenals and Navy yards were much less important than giant civilian aircraft and electronics firms, which became the second half of the "military-industrial complex." Peace leaders like Jane Addams of Hull House and David Starr Jordan of Stanford redoubled their efforts, and now turned their voices against the president because he was "sowing the seeds of militarism, raising up a military and naval caste". Many ministers, professors, farm spokesmen, and labor union leaders joined in, with powerful support from Claude Kitchin and his band of four dozen southern Democrats in Congress who took control of the House Military Affairs Committee.  
Wilson, in deep trouble, took his cause to the people in a major speaking tour in early 1916, a warmup for his reelection campaign that fall.  Wilson seems to have won over the middle classes, but had little impact on the largely ethnic working classes and the deeply isolationist farmers. Congress still refused to budge, so Wilson replaced Garrison as Secretary of War with Newton Baker, the Democratic mayor of Cleveland and an outspoken opponent of preparedness (Garrison kept quiet, but felt Wilson was "a man of high ideals but no principles"). The upshot was a compromise passed in May 1916, as the war raged on and Berlin was debating whether America was so weak it could be ignored. The Army was to double in size to 11,300 officers and 208,000 men, with no reserve, and a National Guard that would be enlarged in five years to 440,000 men. Summer camps on the Plattsburg model were authorized for new officers, and the government was given $20 million to build a nitrate plant of its own. Preparedness supporters were downcast, the antiwar people were jubilant: America would now be too weak to go to war.
The House gutted Wilson's naval plans as well, defeating a "big navy" plan by 189 to 183, and scuttling the battleships. However news arrived of the great sea battle between Britain and Germany, the Battle of Jutland. The battle was used by the navalists to argue for the primacy of seapower; they then took control in the Senate, broke the House coalition, and authorized a rapid three-year buildup of all classes of warships. A new weapons system, naval aviation, received $3.5 million, and the government was authorized to build its own armor plate factory.  The very weakness of American military power encouraged Berlin to start its unrestricted submarine attacks in 1917. It knew this meant war with America, but it could discount the immediate risk because the U.S. Army was negligible and the new warships would not be at sea until 1919, by which time it believed the war would be over, with Germany victorious. The argument that armaments led to war was turned on its head: most Americans came to fear that failure to arm in 1916 made aggression against the U.S. more likely. 
The United States had remained aloof from the arms race in which the European powers had engaged during the decades leading up to the war. The American army numbered slightly more than 100,000 active duty soldiers in 1916; by that time the French, British, Russian and German armies had all fought battles in which more than 10,000 men had been killed in one day, and fought campaigns in which total casualties had exceeded 200,000. In other words, the entire United States Army, as it stood on the eve of intervention, could be wiped out in a single week of the fighting that had characterized the war to date. Americans felt an increasing need for a military that could command respect. As one editor put it, "The best thing about a large army and a strong navy is that they make it so much easier to say just what we want to say in our diplomatic correspondence." Berlin thus far had backed down and apologized when Washington was angry, thus boosting American self-confidence. America's rights and America's honor increasingly came into focus. The slogan "Peace" gave way to "Peace with Honor". The Army remained unpopular, however. A recruiter in Indianapolis noted that, "The people here do not take the right attitude towards army life as a career, and if a man joins from here he often tries to go out on the quiet". The Preparedness movement used its easy access to the mass media to demonstrate that the War Department had no plans, no equipment, little training, no reserve, a laughable National Guard, and a wholly inadequate organization for war. At a time when European generals were directing field armies that numbered several corps, on combat fronts that stretched for dozens or hundreds of miles, no active duty American general officer had commanded more than a division. Motion pictures like The Battle Cry of Peace (1915) depicted invasions of the American homeland that demanded action. 
The readiness and capability of the U.S. Navy was a matter of controversy. The press at the time reported that the only thing the military was ready for was an enemy fleet attempting to seize New York harbor—at a time when the German battle fleet was penned up by the Royal Navy. The Navy Secretary Josephus Daniels was a journalist with pacifist leanings.  He had built up the educational resources of the Navy and made its Naval War College in Newport, Rhode Island an essential experience for would-be admirals. However, he alienated the officer corps with his moralistic reforms, including no wine in the officers' mess, no hazing at the Naval Academy, and more chaplains and YMCAs. Daniels, as a newspaperman, knew the value of publicity. In 1915 he set up the Naval Consulting Board headed by Thomas Edison to obtain the advice and expertise of leading scientists, engineers, and industrialists. It popularized technology, naval expansion, and military preparedness, and was well covered in the media.  But according to Coletta he ignored the nation's strategic needs, and disdaining the advice of its experts, Daniels suspended meetings of the Joint Army and Navy Board for two years because it was giving unwelcome advice, chopped in half the General Board's recommendations for new ships, reduced the authority of officers in the Navy yards where ships were built and repaired, and ignored the administrative chaos in his department. Bradley Fiske, one of the most innovative admirals in American naval history, in 1914 was Daniels' top aide; he recommended a reorganization that would prepare for war, but Daniels refused. Instead he replaced Fiske in 1915 and brought in for the new post of Chief of Naval Operations an unknown captain, William Benson. Chosen for his compliance, Benson proved to be a wily bureaucrat who was more interested in preparing the U.S. Navy for the possibility of an eventual showdown with Britain than an immediate one with Germany. Benson told Sims he "would as soon fight the British as the Germans". Proposals to send observers to Europe were blocked, leaving the Navy in the dark about the success of the German submarine campaign. Admiral William Sims charged after the war that in April 1917, only ten percent of the Navy's warships were fully manned; the rest lacked 43% of their seamen. Light antisubmarine ships were few in number, as if Daniels had been unaware of the German submarine menace that had been the focus of foreign policy for two years. The Navy's only warfighting plan, the "Black Plan" assumed the Royal Navy did not exist and that German battleships were moving freely about the Atlantic and the Caribbean and threatening the Panama Canal. Daniels' tenure would have been even less successful save for the energetic efforts of Assistant Secretary Franklin D. Roosevelt, who effectively ran the Department.  His most recent biographer concludes that, "it is true that Daniels had not prepared the navy for the war it would have to fight." 
By 1916 a new factor was emerging—a sense of national self-interest and American nationalism. The unbelievable casualty figures in Europe were sobering—two vast battles caused over one million casualties each. Clearly this war would be a decisive episode in the history of the world. Every effort to find a peaceful solution was frustrated.
Kendrick Clements claims bureaucratic decision-making was one of the main sources pushing the United States to declaring war on Germany and aligning itself with the Allies. He cites the State Department's demand that Germany's submarines obey outdated 18th century sailing laws as one of the first missteps by the United States bureaucracy regarding the war. By doing so, the United States had essentially given Germany the choice of whether or not the U.S. would enter the war. Secretary of State William Jennings Bryan spent most of the fall of 1914 out of contact with the State Department, leaving the more conservative Robert Lansing with the ability to shape American foreign policy at the time. One of these decisions was made in response to British protests that the Germans were using U.S. radio towers to send messages to their warships. Immediately prior to the war starting in 1914, Britain had cut all cable communications leading out of Germany, including the trans-Atlantic cable. The US Government permitted German embassies to use the US cable lines for "proper" diplomatic business. Germany argued that usage of the towers was necessary to allow efficient contact between the U.S. and Germany. Lansing responded by requiring both sides to give the U.S. Navy copies of the messages they sent over the towers. The French and British were still able to use the cables, ensuring that Germany would be the only belligerent required to provide the U.S. with their messages. This and other seemingly small decisions made by Lansing during this time would eventually stack up, shifting American support towards the Allies. 
Once Germany had decided on unrestricted submarine warfare in January 1917 it tried to line up new allies, especially Mexico. Arthur Zimmermann, the German foreign minister, sent the Zimmermann Telegram to Mexico on January 16, 1917. Zimmermann invited Mexico (knowing their resentment towards America since the 1848 Mexican Cession) to join in a war against the United States if the United States declared war on Germany. Germany promised to pay for Mexico's costs and to help it recover the territory forcibly annexed by the United States in 1848. These territories included the present day states of California, Nevada, Utah, most of Arizona, about half of New Mexico and a quarter of Colorado. British intelligence intercepted and decoded the telegram and passed it to the Wilson administration. The White House would release it to the press on March 1. Anger grew further as the Germans began sinking American ships, even as isolationists in the Senate launched a filibuster to block legislation for arming American merchant ships to defend themselves.  
In early 1917, Kaiser Wilhelm II forced the issue. His declared decision on January 31, 1917, to target neutral shipping in a designated war-zone  became the immediate cause of the entry of the United States into the war.  The Germans sank ten American merchant ships from February 3, 1917, through April 4, 1917, though news about the schooner Marguerite didn't arrive until after Wilson signed the declaration of war.  Outraged public opinion now overwhelmingly supported Wilson when he asked Congress for a declaration of war on April 2, 1917.  It was voted approved by a Joint Session (not merely the Senate) on April 6, 1917, and Wilson signed it the following afternoon.[ citation needed ]
|Ship name||Type||Date||US killed||Total killed||Location||Owner||Sunk by|
|Housatonic||Freighter||Feb 3||0||0||Off Scilly Isles||Housatonic Co.||U-53 Hans Rose|
|Lyman M. Law||Schooner||Feb 12||0||0||Off Sardinia||George A. Cardine Syndicate||U-35 Von Arnauld|
|Algonquin||Freighter||Mar 12||0||0||Off Scilly Isles||American Star Line||U-62 Ernst Hashagen|
|Vigilancia||Freighter||Mar 16||6||15||Off Plymouth||Gaston, Williams & Wigmore||U-70 Otto Wunsch|
|City of Memphis||Freighter||Mar 17||0||0||Off Ireland||Ocean Steamship Company||UC-66 Herbert Pustkuchen|
|Illinois||Tanker||Mar 17||0||0||Off Alderney||Texaco||UC-21 R. Saltzwedel|
|Healdton||Tanker||Mar 21||7||21||Off Holland||Standard Oil||Mine|
|Aztec||Freighter||Apr 1||11||28||Off Brest||Oriental Navigation||U-46 Leo Hillebrand|
|Marguerite||Schooner||Apr 4||0||0||Off Sardinia||William Chase||U-35 Von Arnauld|
|Missourian||Freighter||Apr 4||0||0||Mediterranean Sea||American-Hawaiian Line||U-52 Hans Walther|
Historians such as Ernest R. May have approached the process of American entry into the war as a study in how public opinion changed radically in three years' time. In 1914 most Americans called for neutrality, seeing the war as a dreadful mistake and were determined to stay out. By 1917 the same public felt just as strongly that going to war was both necessary and wise. Military leaders had little to say during this debate, and military considerations were seldom raised. The decisive questions dealt with morality and visions of the future. The prevailing attitude was that America possessed a superior moral position as the only great nation devoted to the principles of freedom and democracy. By staying aloof from the squabbles of reactionary empires, it could preserve those ideals—sooner or later the rest of the world would come to appreciate and adopt them. In 1917 this very long-run program faced the severe danger that in the short run powerful forces adverse to democracy and freedom would triumph. Strong support for moralism came from religious leaders, women (led by Jane Addams), and from public figures like long-time Democratic leader William Jennings Bryan, the Secretary of State from 1913 to 1916. The most important moralist of all was President Woodrow Wilson—the man who dominated decision making so totally that the war has been labeled, from an American perspective, "Wilson's War". 
In 1917 Wilson won the support of most of the moralists by proclaiming "a war to make the world safe for democracy." If they truly believed in their ideals, he explained, now was the time to fight. The question then became whether Americans would fight for what they deeply believed in, and the answer turned out to be a resounding "Yes".  Some of this attitude was mobilised by the Spirit of 1917, which evoked the Spirit of '76.
Antiwar activists at the time and in the 1930s, alleged that beneath the veneer of moralism and idealism there must have been ulterior motives. Some suggested a conspiracy on the part of New York City bankers holding $3 billion of war loans to the Allies, or steel and chemical firms selling munitions to the Allies.  The interpretation was popular among left-wing Progressives (led by Senator Robert La Follette of Wisconsin) and among the "agrarian" wing of the Democratic party—including the chairman of the tax-writing Ways and Means Committee of the House. He strenuously opposed war, and when it came he rewrote the tax laws to make sure the rich paid the most. (In the 1930s neutrality laws were passed to prevent financial entanglements from dragging the nation into a war.) In 1915, Bryan thought that Wilson's pro-British sentiments had unduly influenced his policies, so he became the first Secretary of State ever to resign in protest. 
However, historian Harold C. Syrett demonstrated that business in general supported neutrality.  Other historians state that the pro-war element was animated not by profit but by disgust with what Germany actually did, especially in Belgium, and the threat it represented to American ideals. Belgium kept the public's sympathy as the Germans executed civilians,  and English nurse Edith Cavell. American engineer Herbert Hoover led a private relief effort that won wide support. Compounding the Belgium atrocities were new weapons that Americans found repugnant, like poison gas and the aerial bombardment of innocent civilians as Zeppelins dropped bombs on London.  Even anti-war spokesmen did not claim that Germany was innocent, and pro-German scripts were poorly received. 
Randolph Bourne criticized the moralist philosophy claiming it was a justification by American intellectual and power elites, like President Wilson, for going to war unnecessarily. He argues that the push for war started with the Preparedness movement, fueled by big business. While big business would not push much further than Preparedness, benefitting the most from neutrality, the movement would eventually evolve into a war-cry, led by war-hawk intellectuals under the guise of moralism. Bourne believes elites knew full well what going to war would entail and the price in American lives it would cost. If American elites could portray the United States' role in the war as noble, they could convince the generally isolationist American public war would be acceptable. 
Above all, American attitudes towards Germany focused on the U-boats (submarines), which sank the Lusitania in 1915 and other passenger ships "without warning".    That appeared to Americans as an unacceptable challenge to America's rights as a neutral country, and as an unforgivable affront to humanity. After repeated diplomatic protests, Germany agreed to stop. But in 1917 the Germany military leadership decided that "military necessity" dictated the unrestricted use of their submarines. The Kaiser's advisors felt America was enormously powerful economically but too weak militarily to make a difference.
Twenty years after World War I ended, 70% of Americans polled believed that American participation in the war had been a mistake. 
On April 2, 1917, Wilson asked a special joint session of Congress to declare war on the German Empire, stating, "We have no selfish ends to serve".  To make the conflict seem like a better idea, he painted the conflict idealistically, stating that the war would "make the world safe for democracy" and later that it would be a "war to end war". The United States had a moral responsibility to enter the war, Wilson proclaimed. The future of the world was being determined on the battlefield, and American national interest demanded a voice. Wilson's definition of the situation won wide acclaim, and, indeed, has shaped America's role in world and military affairs ever since. Wilson believed that if the Central Powers won, the consequences would be bad for the United States. Germany would have dominated the continent and perhaps would gain control of the seas as well. Latin America could well have fallen under Berlin's control. The dream of spreading democracy, liberalism, and independence would have been shattered. On the other hand, if the Allies had won without help, there was a danger they would carve up the world without regard to American commercial interests. They were already planning to use government subsidies, tariff walls, and controlled markets to counter the competition posed by American businessmen. The solution was a third route, a "peace without victory", according to Wilson. 
On April 6, 1917, Congress declared war. In the Senate, the resolution passed 82 to 6, with Senators Harry Lane, William J. Stone, James Vardaman, Asle Gronna, Robert M. La Follette, Sr., and George W. Norris voting against it.  In the House, the declaration passed 373 to 50, with Claude Kitchin, a senior Democrat from North Carolina, notably opposing it. Another opponent was Jeannette Rankin, the first woman in Congress. Nearly all of the opposition came from the West and the Midwest.  
The United States Senate, in a 74 to 0 vote, declared war on Austria-Hungary on December 7, 1917, citing Austria-Hungary's severing of diplomatic relations with the United States, its use of unrestricted submarine warfare and its alliance with Germany.  The declaration passed in the United States House of Representatives by a vote of 365 to 1. 
President Wilson also came under pressure from Senator Henry Cabot Lodge, and from former President Theodore Roosevelt, who demanded a declaration of war on the Ottoman Empire and Bulgaria, as Germany's allies. President Wilson drafted a statement to Congress in December 1917 which said "I... recommend that Congress immediately declare the United States in a state of war with Austria-Hungary, with Turkey and with Bulgaria". However, after further consultations, the decision to go to war against Germany's other allies was postponed. 
On January 31, Ambassador Bernstorff presented [...] Germany's response to Wilson's recent 'peace without victory' plea [...]: his nation was about to launch an unrestricted submarine campaign, thereby declaring total maritime war against all neutrals. After February 1, the communique noted, German U-boats would sink without warning belligerent and neutral ships found in a designated zone comprising waters around Great Britain, France, and Italy, and in the eastern Mediterranean. The Admiralty made one minor exception: it would permit one American steamer a week to sail between New York and Falmouth [...]. Initially Germany would grant a period of grace, during which its submarines would not harm neutral ships that either were en route to the war zone or had already arrived.
Several factors led to Wilson's choice. Germany's U-boat warfare was paramount. Had it not been for Berlin's announcement of January 31, the president probably would not have issued a call to arms.
Thomas Woodrow Wilson was an American politician and academic who served as the 28th president of the United States from 1913 to 1921. A member of the Democratic Party, Wilson served as the president of Princeton University and as the governor of New Jersey before winning the 1912 presidential election. As president, Wilson changed the nation's economic policies and led the United States into World War I in 1917. He was the leading architect of the League of Nations, and his progressive stance on foreign policy came to be known as Wilsonianism.
Robert Lansing was an American lawyer and diplomat who served as Counselor to the State Department at the outbreak of World War I, and then as United States Secretary of State under President Woodrow Wilson from 1915 to 1920. A conservative pro-business Democrat, he was a strong advocate of democracy and of the United States' role in establishing international law. He was an avowed enemy of German autocracy and Russian Bolshevism. Before U.S. involvement in the war, Lansing vigorously advocated freedom of the seas and the rights of neutral nations. He later advocated U.S. participation in World War I, negotiated the Lansing–Ishii Agreement with Japan in 1917 and was a member of the American Commission to Negotiate Peace at Paris in 1919. However, Wilson made Colonel House his chief foreign policy advisor because Lansing privately opposed much of the Treaty of Versailles and was skeptical of the Wilsonian principle of self-determination.
The Zimmermann Telegram was a secret diplomatic communication issued from the German Foreign Office in January 1917 that proposed a military alliance between Germany and Mexico if the United States entered World War I against Germany. With Germany's aid, Mexico would recover Texas, Arizona, and New Mexico. The telegram was intercepted by British intelligence.
The history of the United States Navy divides into two major periods: the "Old Navy", a small but respected force of sailing ships that was notable for innovation in the use of ironclads during the American Civil War, and the "New Navy" the result of a modernization effort that began in the 1880s and made it the largest in the world by 1943.
The Tampico Affair began as a minor incident involving U.S. Navy sailors and the Mexican Federal Army loyal to Mexican dictator General Victoriano Huerta. On April 9, 1914, nine sailors had come ashore to secure supplies and were detained by Mexican forces. Commanding Admiral Henry Mayo demanded that the U.S. sailors be released, Mexico issue an apology, and raise and salute the U.S. flag along with a 21 gun salute. Mexico refused the demand. U.S. President Woodrow Wilson backed the admiral's demand. Mexicans of all factions of the Mexican Revolution united against the U.S. demands. The conflict escalated when the Americans took the port city of Veracruz, occupying it for more than six months. This contributed to the fall of Huerta, who resigned in July 1914. Since the U.S. did not have diplomatic relations with Mexico following Huerta's seizure of power in 1913, the ABC Powers offered to mediate the conflict, in the Niagara Falls peace conference, held in Canada. The American occupation of Veracruz resulted in widespread anti-American sentiment.
Arthur Zimmermann was State Secretary for Foreign Affairs of the German Empire from 22 November 1916 until his resignation on 6 August 1917. His name is associated with the Zimmermann Telegram during World War I. He was also closely involved in plans to support rebellions in Ireland and in India, and to assist the Bolsheviks to undermine Tsarist Russia.
The Preparedness Movement was a campaign led by former Chief of Staff of the U.S. Army, Leonard Wood, and former President Theodore Roosevelt to strengthen the U.S. military after the outbreak of World War I. Wood advocated a summer training school for reserve officers to be held in Plattsburgh, New York.
Edward Mandell House was an American diplomat, and an adviser to President Woodrow Wilson. He was known as Colonel House, although his rank was honorary and he had performed no military service. He was a highly influential back-stage politician in Texas before becoming a key supporter of the presidential bid of Wilson in 1912 by managing his campaign, beginning in July 1911. Having a self-effacing manner, he did not hold office but was an "executive agent", Wilson's chief adviser on European politics and diplomacy during World War I (1914–1918). He became a government official as one of the five American commissioners to the Paris Peace Conference of 1919. In 1919, Wilson broke with House and many other top advisers, believing they had deceived him at Paris.
The Allies, or the Entente powers, were an international military coalition of countries led by France, the United Kingdom, Russia, the United States, Italy, and Japan against the Central Powers of Germany, Austria-Hungary, the Ottoman Empire, and Bulgaria during the First World War (1914–1918).
Japan participated in World War I from 1914 to 1918 in an alliance with Entente Powers and played an important role in securing the sea lanes in the West Pacific and Indian Oceans against the Imperial German Navy as a member of the Allies. Politically, the Japanese Empire seized the opportunity to expand its sphere of influence in China, and to gain recognition as a great power in postwar geopolitics.
Woodrow Wilson's tenure as the 28th president of the United States lasted from 4 March 1913 until 4 March 1921. He was largely incapacitated the last year and a half. He became president after winning the 1912 election. Wilson was a Democrat who previously served as governor of New Jersey. He gained a large majority in the electoral vote and a 42% plurality of the popular vote in a four-candidate field. Wilson was re-elected in 1916 by a narrow margin. Despite his New Jersey base, most Southern leaders worked with him as a fellow Southerner.
Defensively equipped merchant ship (DEMS) was an Admiralty Trade Division programme established in June 1939, to arm 5,500 British merchant ships with an adequate defence against enemy submarines and aircraft. The acronym DEMS was used to describe the ships carrying the guns, the guns aboard the ships, the military personnel manning the guns, and the shore establishment supporting the system.
The U-boat Campaign from 1914 to 1918 was the World War I naval campaign fought by German U-boats against the trade routes of the Allies. It took place largely in the seas around the British Isles and in the Mediterranean. The German Empire relied on imports for food and domestic food production and the United Kingdom relied heavily on imports to feed its population, and both required raw materials to supply their war industry; the powers aimed, therefore, to blockade one another. The British had the Royal Navy which was superior in numbers and could operate on most of the world's oceans because of the British Empire, whereas the Imperial German Navy surface fleet was mainly restricted to the German Bight, and used commerce raiders and unrestricted submarine warfare to operate elsewhere.
During World War I, the United States saw a systematic mobilization of the country's entire population and economy to produce the soldiers, food supplies, ammunitions and money necessary to win the war. Although the United States entered the war in April 1917, there had been very little planning, or even recognition of the problems that Great Britain and the other Allies had to solve on their own home fronts. As a result, the level of confusion was high in the first 12 months.
Mexico was a neutral country in World War I, which lasted from 1914 to 1918. The war broke out in Europe in August 1914 as the Mexican Revolution was in the midst of full-scale civil war between factions that had helped oust General Victoriano Huerta from the presidency earlier that year. The Constitutionalist Army of Venustiano Carranza under the generalship of Alvaro Obregón defeated the army of Pancho Villa in the Battle of Celaya in April 1915.
The United States declared war on the German Empire on April 6, 1917, nearly three years after World War I started. A ceasefire and Armistice was declared on November 11, 1918. Before entering the war, the U.S. had remained neutral, though it had been an important supplier to the United Kingdom, France, and the other powers of the Allies of World War I.
The diplomatic history of World War I covers the non-military interactions among the major players during World War I. For the domestic histories of participants see home front during World War I. For a longer-term perspective see international relations (1814–1919) and causes of World War I. For the following (post-war) era see international relations (1919–1939). The major "Allies" grouping included Great Britain and its empire, France, Russia, Italy and the United States. Opposing the Allies, the major Central Powers included Germany, Austria-Hungary, the Ottoman Empire (Turkey) and Bulgaria. Other countries also joined the Allies. For a detailed chronology see timeline of World War I.
The history of U.S. foreign policy from 1913–1933 covers the foreign policy of the United States during World War I and much of the Interwar period. The administrations of Presidents Woodrow Wilson, Warren G. Harding, Calvin Coolidge, and Herbert Hoover successively handled U.S. foreign policy during this period.
The Foreign policy of the Woodrow Wilson administration deals with American diplomacy, and political, economic, military, and cultural relationships with the rest of the world during the Presidency of Woodrow Wilson, 1913–1921. Although Wilson had no experience in foreign policy, he made all the major decisions, usually with the top advisor Edward M. House. His foreign policy was based on the messianic philosophical viewpoint wherein he imagined America had the utmost obligation to spread its principles while reflecting the 'truisms' of American thought.