 Of particular interest for contemporary Iran–United States relations are the repeated accusations that the U.S. government actively encouraged Iraqi leader Saddam Hussein to invade Iran (proponents of this theory frequently describe the U.S. as having given Saddam a green-light), supported by a considerable amount of circumstantial evidence, but the U.S. government officially denies that any such collusion occurred, and no conclusive proof of it has been found.U.S.