Homer is our hero? ("Moe is their leader"?)
Phillip Adams thinks that the Simpsons are "a never-ending version of Fahrenheit 9/11." I don't even know where to start. My impression is that the writers of the Simpsons tend toward the liberal end of the spectrum, especially culturally ("I will not use subliminal messagores", before the 2000 election). But they've always been willing to make fun wherever they see an opening. If George Bush senior has been mocked on the show ("Don't understand the cold drinks. Not my forte."), Bill Clinton has had some remarkably odd appearances ("You think you're not good enough for me, but you are. I've done it with pigs. No fooling! Pigs!" "Aw heck, Quebec's got the bomb.") If the Flanderseses get mocked, Homer, "our hero", is subject to constant humiliation ("Dance, rummy, dance!" "Lisa, I'll give you ten dollars for your rock." "Let's just do this and I'll go back to killing you with beer." "I've been secretly gaining weight to go on disability! Happy anniversary, honey!").
Homer himself is no paragon of anti-Republican beliefs. He's against higher taxes ("We're here, we're queer, we don't want anymore bears!"), homosexuality (until he moves in with those two guys and gets a shih tzu), he attends church, however reluctantly, drinks to excess, works at a nuclear ("It's pronounced 'nu-cu-lar'.") power plant, doesn't let Bart get an earring ("Sparkle sparkle!"), and joins the NRA, which takes offense at his misuse of firearms ("They're for self-defense, killing dangerous or delicious animals, and keeping the King of England off your back."). Lisa, the literal tree-hugger of the family, gets to clean off rocks with her toothbrush instead of baby seals, wants Homer to cook Pinchy so that she can enjoy the smell, is appallingly intolerant of meat-eaters, even in the future ("Because eating meat is wrong." "So very, very wrong." "When will people learn?" "I don't know. I just...don't know."). If Buddha helps people out from Heaven, God's up there too, along with Colonel Sanders.
In fact, at its heart I think that the Simpsons' philosophy is anti-authoritarian. Whether it's Mr. Burns (evil), Chief Wiggum (stupid), Principal Skinner (rigid), or Mayor Quimby (Kennedy-clone), no authority figure comes off well. That's not a political philosophy so much as a social one, and it's not one that either party is willing to adopt. If they're subversive, it's not because they're trying to bring down the Bush/Rove juggernaut (though they may take an occasional swing at it). It's because subversion is funny.
Quotes from memory, which is embarrassing, but is my excuse for any that are wrong. Original article found via the Bunyip.