April of 1917 was the official American declaration of war on the Central Powers. Congress was driven to the decision by three things.
1. The 1915 sinking of the British Lusitania by German submarines. 128 of the lives lost were American.
2. The Zimmerman Telegram, which offered German aid to Mexico for an invasion of the US.
3. The speculation that if the Allied Forces lost, they wouldn't be able to pay America back.
The US did enter World War 1, though not till 1917.
no
1941
1917 smart
1914
It started in 1914
1917
The Jews
Britain's side
by Gerrnan submarine
The Titanic
1917