Tom Skerritt. NYT (share link, may require).
He was 93, and had a heck of a career. A fair amount of genre stuff, some cop/PI stuff, he was Sheriff Bannerman in Cronenberg’s “The Dead Zone” (which I thought was a pretty good King adaptation), he did four episodes of “The F.B.I.”…
…and he was “Robert W. Palmer” the simply irresistible political candidate who has sold his soul to Satan in “The Devil’s Platform” episode of “Kolchak: The Night Stalker”…
…and yes, he did do a “Mannix”. (“Warning: Live Blueberries“, season 1, episode 7. He was “Morgan Carpenter”.)