How is the U.S. attack on Iran any different than what happened to the U.S. when Pearl Harbor was attacked in 1941? Prior to the Pearl Harbor attack the U.S. had not threatened Japan, or attacked any Japanese forces. The major difference of course is that Japan did not attempt to assassinate our President, but the attack was extremely deadly to our armed forces in Hawaii. And it started a long war that resulted in Japan, and Germany's defeat.