The attack on Pearl Harbor cause a number of things. It changed public opinion into entering the war, Americans united behind the "Remember Pearl Harbor", it was loosely used to justify later on the use of the unforgivable atomic bomb. It is important to know, as well, that most Japanese were surprised, apprehensive, and dismayed by the news they were now at war with the U.S. sine the United States was a country that many Japanese admired.
