Question

The United States became involved in the war with Germany because....?

Answer 1

I would have to say because the German dictator was committing a mass genocide?

Answer 2

It depends on which "War with Germany" you're talking about. The U.S. got involved in WW1 because German U-boats were attacking out vessels, to put a halt to our British aid.

If you're referring to WW2, the answer is: Germany declared war on the U.S. four days after Pearl Harbor (Japanese attack on U.S. Naval Base). Hitler chose to declare that the "Tripartite Pact" (German, Italy, and Japan) required Germany follow Japan's declaration of war against the U.S.