Either she's a liberal or she's really, really stupid.
I mean, seriously! Do you think she's ever actually swayed anyone to her side with her arguments who wasn't already solidly there? I think it's pretty obvious she doesn't believe half of what she says; she often seems to say things simply to gain publicity. But those same things are so out there they invariably galvanize the other side.
Conservatives don't want to be aligned too closely with her, and liberals use her as a fundraising and consciousness-raising tool. If she's not a total dumbfrak, she has to be a liberal.