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The US joined United Nations during first world war.President Woodrow Wilson went before a
joint session of Congress to request a declaration of war against Germany.
Wilson cited Germany’s violation of its pledge to suspend unrestricted submarine
warfare in the North Atlantic and the Mediterranean, as well as its attempts to
entice Mexico into an alliance against the United States, as his reasons for
.The Treaty of Versailles was the treaty that set up the League of Nations and not agreeing to it meant not being part of the League of Nations. The next reason that America did not want to get involved in European affairs is because they did not want to risk more Americans dying in a war, as they had in World War I.
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WHY USA JOINED GREAT WAR:
In 1915, several months after Germany started to use submarines in the
war, one of Germany's submarines sunk the British liner Lusitania,
killing 128 Americans. Americans demanded war but President Wilson stood
strong on his stance against war.When Germany sunk another British
liner, the Arabic, in 1915, Berlin agreed to not sink unarmed passenger
ships without warning. Germany continued to sink innocent ships as
apparent when one of its submarines sank a French passenger steamer, the
Sussex. President Wilson informed the Germans that unless they
renounced the inhuman practice of sinking merchant ships without
warning, he would break diplomatic relations, leading to war. Germany
agreed to Wilson's ultimatum, but attached additions to their Sussex
pledge: the United States would have to persuade the Allies to modify
what Berlin regarded as their illegal blockade. Wilson accepted the
Germany pledge, without accepting the "string" of additions. But they
kept on doing it. Another reason is the Zimmerman Telegram a note from
Germany to Mexico but was intercepted by the Brits and sent to the
Americans. The telegram promised Mexico to reclaim its whole southwest
but have to rage war in the US home-front so Germans won't have to worry
that America have to intervene in Europe . Nationalism, Imperialism, Militarism and secret alliances were