Answer :
The U.S. maintained a position of neutrality at the start of World War I in 1914, with prevailing isolationist views among its citizens. Support for Great Britain and France did not unify until 1917, following submarine attacks on American vessels and the Zimmerman Telegram, leading to the U.S. entry into the war.
U.S. Neutrality and Entry into World War I
At the outbreak of war in Europe in the summer of 1914, the United States did not immediately unify in support for Great Britain and France. Dominated by isolationist sentiment, most Americans believed the war was a European affair that should not involve the U.S. However, America's economic connections with Britain and France through trade and loans deepened its involvement inadvertently. It wasn't until the sinking of ships with American civilians, such as the Lusitania in 1915, and the revelation of the Zimmerman Telegram in 1917, that American public sentiment shifted. In April of 1917, amid escalating submarine warfare and threats to its nationals and interests, the U.S. declared war on Germany.
President Woodrow Wilson had initially maintained a stance of neutrality while advocating for democracy. Trade with Allied nations had increased significantly compared to that with the Central Powers. With the resurgence of unrestricted German submarine warfare and the impacts on American lives and shipping, combined with the potential geopolitical shifts in power, the U.S. finally moved from neutrality to direct involvement, rallying the nation's military resources and civilian support for the war effort.
