After maintaining neutrality for the first three years of the war, the United States decided to formally enter the First World War on 6th April 1917. Beginning their position with predictable, traditional neutrality when the war broke out in 1914, the United States evaded war in accordance with their long-running central theme in foreign policy, avoiding ‘entangling alliances’. The complex set of circumstances that eventually led to the involvement of America in the First World War, results in there being no singular culprit or simple explanation for their original non-involvement transforming into a fairly unprecedented attack on the German forces. However, as a result of a long battle of Woodrow Wilson’s conscience concerning peace ideals, developing sympathies with Britain and a growing intolerance for increasingly belligerent German military tactics as the war progressed, an association with the Allied forces became ever more likely. On 2nd April 1917, President Wilson finally made an address to a joint session of Congress requesting a declaration of war against Germany, and that the United States should shed their neutrality and enter world war.
In terms of American idealism, it was inevitable that the United States should see the war from the perspective of a neutral base; ever since Thomas Jefferson’s first inaugural address in March 1801, American foreign policy has enjoyed ‘entangling alliances with none’ as a key feature. Historian Ronald Powaski asserted that in avoiding such alliances, it was paramount that the United States should not concern itself with issues of countries afar, especially European wars – an issue President Wilson recognised swiftly upon the outbreak of war. Wilson was a dedicated progressive internationalist at the outbreak of war, resulting in his assertion of isolationist policies in the beginning in order to preserve these ideals of opposition to war through asserting and maintaining peace; his ultimate goal for war time was to become an external mediator between the two sides. This being a position that required complete objectivity, Wilson ensured the country’s neutrality upon the war’s commencement. The President’s handling of the war in his first term in office won him the admiration of popular progressive internationalist groups, such as the Woman’s Peace party, who believed that Wilson was at least in part avoiding war in recognition and respect of the sacredness of human life.
Regardless of American ideals of an association of peaceful nations by way of disarmament and international friendship, the war in Europe raged on. In accordance with Thomas Knock’s description of the impact of internationalism on Wilson’s perspective on war, with the increasing loss of life and the determined belligerence of the German forces, all progressive internationalists accepted that eventual United States involvement in the First World War was inevitable, and that the best way for Wilson to move forward would be to intervene in an attempted arrangement of peaceful agreement, thus Wilson proposed the ending of war without a victor. However, Knock continues, with Germany’s violent rejection of ‘peace without victory’ being illustrated by the sinking of a further three American ships, Wilson had no choice but to meet the German forces with strength in an attempt to prevent further unjustified killing; though Wilson’s goal of ensuring the world was a safe and peaceful place for the development of democracy and internationalism did not change, by April 1917 Wilson realised that he now had to join the war to end it. 
On the other hand, Wilson’s personal perspective of the value of war and his goals for world democracy are, understandably, not the sole reason for Congress to agree to wage war on another country. One of the main points to consider when studying why the United States entered the war in 1917 as opposed to 1914, has to be the economic implications of such a conflict; being such a significant economic power, the financial and industrial effects of any political judgement – particularly going to war – would have certainly had a huge impact. George Herring emphasises the fact that ‘trade was so important to Europe and the United States itself that whatever Americans did or did not do would have an important impact of the war and the domestic economy’; the reality was that it was almost implausible that the United States could remain unaffected by the war as it progressed. The United States aimed to protect shipping and trading rights by remaining neutral, in an attempt to retain the ability to trade to both sides of the war effort since it was assumed that their own economy would suffer if cut off from either the German or British markets, as it was permitted to do under the Hague Convention of 1907. By maintaining their neutrality from the onset of the war, they hoped to profit from all belligerents by manufacturing munitions, hence promoting their own economic growth and industrial prosperity.
However, German-American trading was blockaded by the British with an ever-growing list of contraband items; this meant that despite theoretical neutrality, the United States were, in practice, supporting the Allies by only supplying and arming their forces. Upon the dramatic increase of the purchasing of war materials by the Allies from the United States between 1914 and 1916, with total exports swelling from $40,000,000 to $1,290,000,000, the economic interests of the United States were now focussed on industrial growth through trading with the Allies as opposed to fighting for free trade with German forces. This also developed an interdependency between the Allied forces and the United States – a dependency for war materials from the British and French especially and an economic reliance on the part of the Americans. Such an interdependency furthered the emerging political alliances between the two, which H.C. Engelbrecht and F.C. Hanighen suggest explains in part the late entrance of the United States into the First World War.
Alongside acceptance of the British blockade binding the United States and British forces, JP Morgan’s subsidising the Allies’ financial issues by assuming the role of an Allied purchasing agent in the United States as well as government-approved credit was a step towards losing objectivity in the war, which ultimately took the United States a step closer to joining the war effort. With the distinction between a loan and credit being so clearly determined, the United States was finally allowed to extend credit to the Allies – an allowance which they took advantage of to the sum of $80,000,000 over the next six months. It is clear that as the war progressed America became more deeply entwined in ‘entangling alliances’ that drew them ever closer to the precipice of war.
Also influencing the timing of the United States’ entrance into the First World War, was their turbulent relationship with Britain. The United States took issue with the increasing belligerence of Allied forces, particularly the British. In part, it was the imposition of strict contraband lists which offended American ideals of free trade that alienated the United States from joining arms with the Allies. Since the British held such tremendous sea power, they had the resources and standing to use sheer force and aggressive tactics. However, this soon proved to be profitable to the United States as the British fell short of resources and desperately needed to tap into American industrial power, providing a suddenly less offensive strategy. Another significant friction between Britain and the United States was the disagreement caused by Britain’s ruthless suppression of the 1916 Irish rebellion and the violent condemnation of its leaders. Though, as the war progressed, Wilson became increasingly sympathetic with Britain, proclaiming in May 1915 that despite their disagreements over blockades and freedom of the seas ‘England is fighting our fight’. Wilson and the whole of the United States began to realise that at this point it was inevitable that they would join the war on the side of the Allies. Michael Lind elaborates on Walter Lippmann’s assertion that the United States would have to fight with Britain now or face a separate war against an expansionist German empire in the near future; in declaring that England was fighting the fight of the United States, Lind argues, Wilson was coming to recognise the power of Germany and its very real threat to global democracy. If Germany were to win the war, the United States would have to quickly develop its military and naval resources to prepare for the new state of political instability that would be aroused by a successful German imperialist conquest. By 1917, it was simply a case of questioning the United States’ preparedness in terms of national security. The progressively aggressive German forces required a marriage of both the powers of the United States and the Allies to finally bring to an end the First World War.
Whilst President Wilson embraced German ideals of authoritarianism and expansionism, with some historians, such as Jonah Goldberg, going as far as to say he was fascist by nature, the way in which the Central Powers sought to gain victory in the First World War offended both Wilson and his country. Almost certainly, it was the actions of the German forces growing intolerable that caused the United States to enter war when they did. Wilson was enraged when the British Isles were declared a war zone by Germany in February 1915, effectively justifying any loss of life that should occur in the area, neutral or not. Herring offers that upon the death of an American citizen one month later in the sinking of the Falaba, we see a ‘hint of future crises’ since Wilson swore to hold Germany fully accountable for its movements. Continuing, Herring illuminates the bombardment of attacks that take the lives of theoretically neutral United States citizens over the next few years, including the sinking of the Lusitania in May 1915 taking 128 American lives. Additionally, the sinking of the Sussex in March 1916, the sinking of the Laconia in February 1917 and the attack on three American merchant ships in March 1917 all represent Germany’s relentlessly violent offense strategies. Having attempted to remain a neutral party in order to promote Wilson’s ideals of progressive internationalism and peaceful international unity, it became clear that the crisis in Europe had to be countered from an offensive standpoint – Wilson could no longer play his desired role of an external mediator.
Though the US-British relationship was under immense strain following blockade strategies and the brutal suppression of the Easter Rebellion of 1916, aggressive German war tactics and the loss of American lives eventually proved to be too severe. It is certain that the United States’ timing with regards to entering the war effort was affected significantly by economic profitability; H.C. Engelbrecht and F.C. Hanighen prompt that ‘when the armistice was signed in 1918, there were 21,000 new American millionaires’ that had been created by the United States taking advantage of the need of both sides of the war effort to purchase war materials. In effect, the United States used the First World War to first and foremost stabilise and grow their own economy before allowing themselves to become entangled in an alliance with a single side. Additionally, Wilson’s peace ideals and the United States’ penchant for neutrality also played a part in the delayed war entry. It is evident that despite Wilson’s attempts to keep the United States out of war in the opening years, his decision to request entry was a reaction to increasingly difficult circumstances in Europe that required his address.
 ‘Thomas Jefferson First Inaugural Address’, The Avalon Project at Yale Law School, <http://avalon.law.yale.edu/19th_century/jefinau1.asp> [accessed 11 October 2014].
 R. Powaski, Toward an Entangling Alliance: American Isolationism, Internationalism and Europe, 1901 – 1950 (Westport: Greenwood Press, 1991), p.7.
 T. Knock, ‘Wilson’s Battle for the League: Progressive Internationalists Confront the Forces of Reaction’, in D. Merrill and T. Paterson (eds.), Major Problems in American Foreign Relations: Documents and Essays, Volume 1 (Boston: Houghton Mifflin, 1999), pp. 523-525.
 Knock, ‘Wilson’s Battle for the League: Progressive Internationalists Confront the Forces of Reaction’, pp.525-528.
 G. Herring, From Colony to Superpower: U.S. Foreign Relations since 1776 (Oxford: Oxford University Press, 2008), pp.400-401.
 H.C. Engelbrecht and F.C. Hanighen, The Merchants of Death (New York: Dodd, Mead, and Co., 1934), pp.173-175.
 Herring, From Colony to Superpower: U.S. Foreign Relations since 1776, pp.400-401.
 Herring, From Colony to Superpower: U.S. Foreign Relations since 1776, p.404.
 A. Rice Pierce, Woodrow Wilson and Harry Truman: Mission and Power in American Foreign Policy (Westport: Greenwood Publishing Group, 2003), p.25.
 M. Lind, The American Way of Strategy: U.S. Foreign Policy and the American Way of Life (New York: Oxford University Press, 2006), p.94.
 Herring, From Colony to Superpower: U.S. Foreign Relations since 1776, p.405.
 J. Goldberg, Liberal Fascism: The Secret History of the Left from Mussolini to the Politics of Meaning (New York: Doubleday, 2007), pp.78-87.
 Herring, From Colony to Superpower: U.S. Foreign Relations since 1776, p.402.
 Engelbrecht and Hanighen, The Merchants of Death, p.173.