Silver has always identified himself as a liberal, but he's never followed the "party line." He was one of Giuliani's earliest and most outspoken supporters (I know -- some people might say that makes him even more "liberal"), and has always stood up for what HE thinks is right. If only more Hollywood lefties were as independent-minded as him.
I also have to say a kind word about Sheen. As much as I disagree with his views, years ago I saw him walking in midtown Manhattan. I'd just seen the miniseries JFK, where I thought he did a great job portraying Pres. Kennedy. (Wonder what JFK would think of the Iraq appeasers.) Being a bit starstruck (and interested in a showbiz career at the time), I approached him and asked him about the obstacles he faced in his own career. To my surprise, he spent about 10 minutes talking to me in a very avuncular fashion.
His main point was, if you're going to enter show biz (or I guess any career where the odds are difficult), you have to thoroughly believe in and love what you're doing, and not think about the money at that beginning stage. Platitudes, perhaps, but the sincerity and generosity with which he conveyed them really struck me. Thus no matter how dopey his political activism gets, I still have a soft-spot for him.