Bruce Wayne (Batman): Republican. Philanthropic, pro-business, and extremely tough on crime; the original compassionate conservative. If Gotham's anything like other big cities in its region, it's probably heavily Democratic, so Bruce probably backs a fair number of Dem candidates. (Wayne Manor is actually in Bristol, outside the city, so Bruce doesn't vote in Gotham anyway. But for my money, Lucius Fox is a huge kingmaker in Gotham's Democratic Party.) Favorite politician: Rudy Giuliani. Even if he is a pussy.
Jim Gordon: Democrat. C'mon, he's from Chicago; it's required. Hell, he moved away fifteen years ago and he's probably still voting Democratic there. I do see Jim as a very conservative Democrat, though.
Leslie Thompkins: Green. Voted for Nader last time. Might actually vote for him again even if this election's critical, because Kerry's such a goddamn right-winger these days.
Alfred Pennyworth: American citizen, or a permanent resident? Got me. My bet, assuming the former: he listens very carefully to everything Leslie says, takes the filled-out sample ballot she gives him into the voting booth -- and then votes the exact opposite.
Barbara Gordon (Original Batgirl, Oracle): Democrat. I see Babs as fairly liberal, more so than her dad, but with some strong conservative streaks. My guess is she's pro-choice, but thinks three strikes laws are a great idea.
Dick Grayson (Robin I, Nightwing): More liberal than Bruce, more conservative than Babs. Votes his conscience; registers as a Democrat to piss off Bruce.
Cassandra Cain (Batgirl): ...is Cass 18 yet? Not that it matters. Doesn't vote. Doesn't care.
Tim Drake (Robin III): too young to vote. Not too attracted to either of the major parties. Probably will register as Independent, maybe Libertarian.
Jason Todd (Robin II): dead. Like Jim Gordon, voting Democratic in Chicago.
Stephanie Brown (Spoiler, Robin IV): canonically Republican (Robin #44, I think); recently re-registered in a new polling location with a change of parties.