How did America get involved in war world 1?

There are Two reasons why the U.S joined the war.

1. Geramany was using a war tactic called unrestricted warfare, which means they were bombing random british ships. They ended bombing a british ship that contained 128 American civilans. The U.S was ouraged of course and pres. wilison sent out a warning to Germany, telling them to stop hitting random ships. They only attacked british ships for a while, but then went back to unrestricted warfare. Bombing more ships. American was already angry that their citzens were in danger and Pres. Wilson kept telling the Germans too stop.

2. The zimmerman note, is a telegram that was sent to Mexico saying that the Germans will help the Mexicans reclaim the land that they lost from the Americans if they joined the war on their side which was the central powers. This really ticked off the pres. and American people. They were really pissed and this cause them too join the war. They already favored the allies, so they joined that side and the U.S was in the war.