American entry into the First World War marked a radical transformation in the nation’s approach to world affairs. While the extent to which notions of isolationism dominated common perceptions regarding the United States’ role in the world tend to be a little exaggerated, President Woodrow Wilson’s decision to send American troops across the Atlantic Ocean to engage in the European conflict did mark something of a repudiation of isolationism as an influential force in American foreign policy.
Wilson had been extremely reluctant to engage the United States in the ongoing war in Europe. He believed it was preferable to remain neutral, and later be able to negotiate a new world order with less war by decreasing the factors that lead to war. Wilson’s “Fourteen Points,” issued after America’s entry into the war in 1917, reflected the president’s desire to eliminate Europe’s legacy of interborder disputes. Europe’s war was exacerbated by a history of secretive negotiations and arrangements the aggregate result of which was a broader military conflict than otherwise might have been the case.
It was Germany’s decision to engage in submarine warfare against merchant shipping from North America to Europe. The consequent sinking of the ocean liner Lusitania forced Wilson’s hand, combined with another, less well-known development. Wilson found that Germany was attempting to attain Mexico’s agreement to enter the war against the United States. Germany promised to return to Mexico American territories once held by the country in exchange for the latter’s declaration of war against the United States. Upon learning of this, the United States’s path to war was set.
While American entry into World War I marked a dramatic shift away from neutrality or isolationism, it did not end its isolationism. Wilson’s painstaking effort at creating a League of Nations was doomed to failure when Congressional opponents, mainly among Republicans, resisted institutionalized American engagement in European affairs. To that extent, America’s approach to international affairs remained closely tied to the old isolationist sentiments of the past. For that reason, US participation in World War I as a combatant only partially marked a transition that would be concluded with the Japanese attacks on American military installations in Hawaii and the Philippine Islands twenty years later.