- Anti-German propaganda: Media outlets and the government actively promoted anti-German sentiment, presenting Germany as a threat to American values and interests.
- Atrocity stories: Gruesome accounts of German brutality, such as the invasion of Belgium and the sinking of the Lusitania, fueled public outrage and created a sense of moral duty to oppose the Central Powers.
2. Economic Ties and Trade:
- Trade disruption: The British blockade and German submarine warfare disrupted American trade with both Allied and Central Powers, leading to economic losses and a desire to protect business interests.
- War loans: The United States had provided significant loans to the Allied powers, and the possibility of default if the Allies lost added economic incentive to support the Allied cause.
3. Violations of International Law:
- U-boat warfare: Germany's unrestricted submarine warfare violated international law and endangered neutral shipping, including American vessels.
- Belgian neutrality: The German invasion of neutral Belgium in 1914 directly challenged the principle of territorial integrity and neutrality.
4. Cultural and Ethnic Affinities:
- Many Americans had close ties to Britain and other Allied countries through family, cultural heritage, and shared values, fostering sympathy for the Allied cause.
5. Wilsonian Ideals:
- President Woodrow Wilson's idealistic vision of a world made "safe for democracy" resonated with many Americans who saw the war as a fight for democratic principles and against autocratic regimes.
- The Fourteen Points: Wilson's Fourteen Points peace proposals, which advocated for self-determination and a just peace, further aligned American values with the Allied cause.
6. Zimmerman Telegram:
- In 1917, the British intercepted and shared with the United States a telegram sent by German Foreign Minister Arthur Zimmerman, proposing an alliance with Mexico against the United States.
- This revelation sparked indignation and solidified public support for joining the war.
7. Unrestricted Submarine Warfare:
- Germany's resumption of unrestricted submarine warfare in early 1917, disregarding American warnings, directly threatened American lives and interests, leading to the United States' declaration of war.
It's important to note that not all Americans opposed the Central Powers; there were pockets of pro-German sentiment, particularly among German-American communities and some pacifists. However, the factors listed above contributed significantly to the majority's support for joining the war on the side of the Allies.