Actually I always thought Ian McDiarmid, (at least as Senator Palpatine), bore an uncanny resemblance to Joe Lieberman.
People tell me I resemble McDiarmid, too. I dunno to quite how to take that.
Lieberman? Hmmm...yeah I can see that For Halloween, all you need is a cape and a cane!
One of the best scenes ever filmed:
http://www.youtube.com/watch?v=R09jFWQVrE0
His expression at 1:26 is so evil...should have been nominated for an Oscar.