It would be because of resuming the unrestricted submarine warfare that resulted of the sinking of a passenger ship Lusitania that killed american passengers and also the Zimmerman telegram that invites the Mexican government to join the Central Powers and after winning the war they would receive the lands they lost to the United States. President Woodrow Wilson turns the war into an ideological crusade through fighting to make the world safe for democracy and defeat the forces that wants to destroy democracy.
