No doubt, the early war hero turned traitor is one of the more infamous figures in American history. Some may not consider him a spy in the pure sense of the word, but no one doubts Benedict Arnold turned sides mid-war and was going to surrender the American fort at West Point, New York, in return for money and a command in the British army. The plot was uncovered in time, and Arnold escaped. It was Major John Andre, another spy, who helped convince Arnold to switch sides.
