It's a damn shame, this guy was a combat fighter pilot and war hero. I want to believe it's just a case of a good person being human and doing bad things, lots of bad things, in the highest congress in the world.
I've heard that a good combat pilot climbs into his cockpit utterly convinced that he will never get hit, that he's 10 feet tall and bulletproof. In Duke's case, this might explain some things.