Why did the United States become involved in World War I?

Germany attempted to instigate a conflict between the United States and Canada to draw American attention away from Europe.

It came in part from the unrestricted submarine warfare Germany waged on all nations that traded with its enemies.

The United States entered the war as a requirement of the American-French alliance from the Revolutionary War.

An attempted assassination of President Wilson by a German-born American convinced the United States to enter the war.

HAS TO BE ONE OF THE ANSWERS ABOVE

The main reason the United States became involved in World War I was due to Germany's unrestricted submarine warfare on all nations that traded with its enemies. This directly affected American interests and ultimately led to the U.S. declaring war on Germany.