1. Lusitania Sinking: The sinking of the British passenger ship RMS Lusitania by a German U-boat in May 1915 was a significant event that contributed to the US decision to enter the war. Over 100 American citizens died in the attack. Germany's unrestricted submarine warfare policy in the Atlantic, which targeted both military and civilian ships, caused outrage and increased public support for intervention in the United States.
2. Zimmermann Telegram: In early 1917, the British intercepted and decoded a telegram sent by German Foreign Minister Arthur Zimmermann to the German ambassador in Mexico. The telegram proposed an alliance between Germany and Mexico, promising to help Mexico regain its lost territories in Texas, New Mexico, and Arizona. This revelation further inflamed anti-German sentiment in the United States.
3. Economic Ties and Loans: The United States had significant economic ties with the Allied Powers (Britain, France, and Russia) and was providing them with loans. The European allies owed large sums to American banks, and there were concerns that their defeat would jeopardize the repayment of these loans.
4. Allied Propaganda and Atrocity Claims: The Allied powers effectively utilized propaganda to depict Germany as an aggressor and responsible for atrocities against innocent civilians. Reports of German soldiers committing acts of brutality and sinking neutral ships generated widespread sympathy for the Allied cause.
5. Perceived Threat to Democracy: World War I was seen by many Americans as a struggle between democratic ideals and autocratic regimes. The spread of democratic principles was a core foreign policy objective, and the success of the Allies was viewed as a means to promote democracy worldwide.
6. Moral Obligation: Some Americans felt a moral obligation to support the Allies, particularly those of British descent or with close cultural and historic ties to European nations.
7. Neutrality Violations: Germany's continued violations of American neutrality rights also contributed to growing frustration. Despite US warnings, German submarines continued to sink unarmed ships and attack US merchant vessels.
8. Wilsonian Ideas: President Woodrow Wilson's belief in the principles of democracy, collective security, and the self-determination of nations influenced his decision to join the war. He saw the conflict as an opportunity to create a more just and secure world order.
In summary, the US government's decision to engage in World War I was influenced by a complex combination of factors including the Lusitania sinking, the Zimmermann Telegram, economic ties and loans, Allied propaganda, the perceived threat to democracy, moral obligation, neutrality violations, and President Wilson's ideas about international relations.