on June 29 of 1914, a nationalist Serb from Bosnia murders the heir to the throne of austria and his wife in Sarajevo
After the assassination, Austria-Hungary accused Serbia of having organized attacks and declares war, the conflicts spread between the triple entente and the triple alliance.
The united states finds iself being a victim of a comercial blockade of the atlantic so they decide to go to war and fight alongside with the allies
The zimmermann telegram caused the united states to go to war against germany thanks to the united states having submarines in the atlantic which were able to catch this telegram which was actually meant for mexico.
the german sinking of RMS Lusitaniua on may 7, 1915 which caused the loss of 128 lives USA citizens provoked great anger.
president woodrow wilson decleared war against germany and focused on 2 themes, the reeintroductin of german unrestricted submarine warfare was uncruel and unmanly business and second he implied moral superiority of free democratic nations