What caused World War I and why did the U.S. become involved?

During the early 1900’s, tensions in Europe developed as a result of Militarism, Alliances, Imperialism, and Nationalism.

WWI’s immediate cause was the assassination of Archduke Francis Ferdinand in 1914. (Austrian) Archduke Francis Ferdinand  (Serbian) Gavrilo Princip 

After the assassination, two sides were formed in Europe (the Allies and the Central Powers) and WWI began. Central Powers  Allies  vs.

President Woodrow Wilson (1913 – 1921) When WWI began, President Woodrow Wilson declared U.S. neutrality. President Woodrow Wilson (1913 – 1921)

German U-boat (military submarine) Despite U.S. neutrality, German submarines (U-boats) attacked U.S. merchant ships. German U-boat (military submarine)

As a result, a major reason the U. S As a result, a major reason the U.S. entered WWI was to maintain freedom of the seas for U.S. ships.

President Wilson persuaded Congress to enter WWI in 1917 by arguing that the U.S.’s involvement would make the world “safe for democracy”. President Wilson asking Congress to declare war on Germany; April 2, 1917  War declared by Congress on April 4, 1917