Which event most influenced President Woodrow

Wilson's decision to enter World War I?

(1) defeat of Russia by Germany

(2) assassination of Archduke Franz Ferdinand

(3) raids by Mexico on the southwestern United

States

(4) renewal of unrestricted submarine warfare by

Germany

The correct answer is (4) renewal of unrestricted submarine warfare by

Germany

Unrestricted submarine warfare basically meant that Germans declared themselves to be in charge of the seas and anyone who was found in the seas would be attacked, regardless of their affiliation such as being a civilian or a military ship. They attacked a ship that belonged to the US and this was the final straw that made the US join the war.

It was the " (4) renewal of unrestricted submarine warfare by Germany" that most influenced President Woodrow Wilson’s decision to enter World War I.