Flip-flop is a mild word to describe McCain's position on issues. After being a lead sponsor of Amnesty legislation, he now pretends to support law enforcement efforts to stop the illegal alien invasion.
Before that, McCain was a key figure in persuading Congress to abandon Missing in Action POWs left in VietNam. He has also supported the official government cover-up of the 1967 Israeli attack on the USS Liberty. One could go on.