Of course, the comparison is more than a little strained.
As Gary Oldman's Commissioner Gordon says of the hated and hunted Batman, 'He has to run away -- because we have to chase him.' That's real moral complexity. And when our artistic community is ready to show that sometimes men must kill in order to preserve life; that sometimes they must violate their values in order to maintain those values; and that while movie stars may strut in the bright light of our adulation for pretending to be heroes, true heroes often must slink in the shadows, slump-shouldered and despised -- then and only then will we be able to pay President Bush his due and make good and true films about the war on terror. Perhaps that's when Hollywood conservatives will be able to take off their masks and speak plainly in the light of day.
Once again, Frank Miller is really good for a take on Batman as something of a right-winger, but it has nothing in common with what Limbaugh describes. Batman never kills. Batman struggles constantly with his conscience, but he never "violates his values." The Batman identity is not a compromise. It is an end in itself. Bruce Wayne never had any interest in becoming a cop, and he has no desire to "take off [his] mask and speak plainly in the light of day."
The Batman is not a good man driven underground. In many ways, he is a bad man, but he is the best of bad men. Most importantly, Batman is not the justice system, and does not desire its sanction. Batman is not an argument for legalizing torture. If you want to make that argument, you need to examine Jim Gordon. Batman does not tell you how to run a society or how to deal with other people. In fact, the dysfunction of the Bat-family/society is a common theme of the comic books. Batman is not and cannot be an argument for any government, right or left. Superman is your man for that. He's the one interested in the effect that his actions have on society. Batman just wants to knock out the punk taking the old lady's handbag. (Every once in a while you get hints in the comics books that demonstrable involvement by the Batman in a criminal case is enough to get charges thrown out of court. This idea, the logical opposite of the ridiculous image of a masked man testifying in court, is underexplored.)
I'm not really interested in arguing politics here. In fact, I would be deeply interested in a conservative reading or re-imagining of the Batman. It just has to be better than Limbaugh's.