The first was unrestricted submarine warfare. The German U-boats were ordered to sink all ships in sight friendly or not. So once the U-boats sank the Lusitania we were given another reason to join the fight. With this we created the convoy system. The second reason was, of course, money. With the other countries taking loans from the U.S. we wanted to ensure that we would get our money. The only real way to ensure this was to join the war. The third is the Zimmerman Note. This was a note sent to Mexico from the Germans that tried to convince the Mexicans to join the Germans with promises of getting there land back in the U.S. The fourth reason is because Russia drops out. This is because the Zar family is taken out of power and killed. With Russia out, the war went from a 2 front war to a 1 front
The first was unrestricted submarine warfare. The German U-boats were ordered to sink all ships in sight friendly or not. So once the U-boats sank the Lusitania we were given another reason to join the fight. With this we created the convoy system. The second reason was, of course, money. With the other countries taking loans from the U.S. we wanted to ensure that we would get our money. The only real way to ensure this was to join the war. The third is the Zimmerman Note. This was a note sent to Mexico from the Germans that tried to convince the Mexicans to join the Germans with promises of getting there land back in the U.S. The fourth reason is because Russia drops out. This is because the Zar family is taken out of power and killed. With Russia out, the war went from a 2 front war to a 1 front