Why America enters the war?

Answer 1

America enters into war when our safety or interests are at risk or the safety and interests of our allies is threatened.

Answer 2

America entered World War I primarily because of Germany's unrestricted submarine warfare, which led to the sinking of American ships and loss of American lives. Additionally, American public opinion was also swayed by Germany's attempts to make an alliance with Mexico and the famous Zimmermann Telegram. Lastly, a desire to ensure a more stable world order and protect American economic interests also played a role in America's decision to enter the war.