@Strandjunker
Good question! Almost all good historians will cite many factors to account for any important event.
IMO anger & hate is the easiest methods for a politician to jump to the top of the political pyramid. The U.S. has a long history of hating immigrants and various schemes to make their lives miserable.
Also, after the end of the Cold War, the U.S. was looking around for its next enemy to justify it global reach. It's has made enemies in Latin America, Asia and Europe.