Sorry to bump up an old thread but I've been reading through this and I am surprised people didn't know Marvin was a Democrat. Just because he was in three movies with John Wayne didn't mean he shared his views.
First of all, I'd like to welcome you here to this great message board for John Wayne and friends.
Yes, you are right about Lee Marvin. But if you read what I said just above you, you will see that he kept a low profile as far as I know. I think he was a fine man. So I'm not sure what you point is, and know that John Wayne worked with many Democrats. He was the one in a minority.
Cheers Hondo Duke Lane