I always had some idea that Sterling Hayden was a communist.
I had to do some searching but I found this comment
“His great admiration for the bravery of the Communist partisans led to a brief membership in the Communist Party. Sterling Hayden was apparently active in supporting an effort by the Communist-controlled motion picture painters union to absorb other film industry unions. As the Red Scare deepened in U.S., he cooperated with the House Un-American Activities Committee, confessing his brief Communist ties and “naming names.” His wife at that time, Betty de Noon, insisted that the names her ex-husband provided were already in the hands of the committee, which had a copy of the Communist Party’s membership list. In any event, Hayden subsequently repudiated his cooperation with the committee, stating in his autobiography, “I don’t think you have the foggiest notion of the contempt I have had for myself since the day I did that thing.” Sterling Hayden died of prostate cancer in Sausalito in 1986, age 70.”
He was a big fan of Tito. He goes into a little detail in this interview.