1. Isolationist Sentiment: At the beginning of World War I, the United States had a strong tradition of isolationism, meaning it sought to avoid involvement in foreign conflicts and focus on domestic matters. Isolationists believed that involvement in European wars would only divert resources and energies away from the nation's development.
2. Neutrality: President Woodrow Wilson initially tried to maintain U.S. neutrality despite growing tensions and pressures. He believed that the best way to serve American interests was to remain impartial and avoid taking sides, although public opinion became increasingly divided between those who favored the Allies (Britain, France, and Russia) and those who supported Germany and Austria-Hungary.
3. Submarine Warfare and the Zimmermann Telegram: The unrestricted submarine warfare campaign waged by Germany, which resulted in the sinking of American merchant ships and the loss of American lives, played a significant role in pushing the United States toward war. Additionally, the interception and publication of the Zimmermann Telegram - a secret message from Germany proposing an alliance with Mexico to invade the United States - further inflamed public sentiment and convinced many that Germany posed a direct threat to American security and interests.
4. Economic Factors: The economic ties between the United States and the Allied nations influenced the decision-making process. The Allies heavily relied on American supplies and financial support, and their economies were closely linked. Supporting the Allies, therefore, made economic sense for the United States.
5. Public Pressure and Propaganda: As public opinion in the United States shifted toward supporting the Allies, pressure mounted on the government to take action. Propaganda campaigns and media coverage fueled strong anti-German sentiments and reinforced the idea that the United States had a moral obligation to intervene and protect democracy and freedom in Europe.
Ultimately, a combination of factors, including the unrestricted submarine warfare campaign, diplomatic incidents like the Zimmermann Telegram, economic considerations, public pressure, and propaganda contributed to the United States joining World War I in 1917. While it is impossible to state with certainty whether the country could have remained neutral indefinitely, these factors played a significant role in shaping its decision.