Answer :
The U.S. entered WWI due to the Zimmerman telegram and U-boat attacks, tilting the war's outcome towards the Allies. Post-war, President Wilson's Fourteen Points and the League of Nations, which the U.S. never joined, influenced international relations and highlighted U.S. economic and moral leadership.
The United States entered World War I in 1917 after maintaining a policy of neutrality under President Woodrow Wilson. The interception of the Zimmerman telegram, which revealed a German proposal to Mexico for an alliance against the U.S., coupled with a series of aggressive U-boat attacks, pushed the U.S. to abandon its neutral stance and join the Allies. U.S. participation provided the necessary manpower and resources that helped tip the balance on the Western Front in favor of the Allies.
After the war, President Wilson was instrumental in the creation of the League of Nations, an international organization designed to prevent future conflicts. Although the U.S. Congress did not ratify the Treaty of Versailles and the U.S. never joined the League, the ideas of Wilson's Fourteen Points influenced the post-war world order, promoting principles such as self-determination, free trade, open diplomacy, and collective security. Wilson's vision highlighted the U.S. as a rising economic power and moral leader post-WWI, shaping the international climate towards democracy.
The Impact of U.S. Economic Power during the conflict was also significant, as American trade with the Allied powers grew while trade with the Central Powers diminished almost entirely. The U.S. emerged from the war as a creditor nation with a strong economy capable of influencing global markets and politics. This consolidation of U.S. economic influence continued throughout the 1920s and played a key role in world affairs.
