Usually, the corrupt politician is listed as a conservative. I've seen the joke many times in many forms. Personally, I think it works best without trying to demonize any political party. But I can't really expect too much from someone who, despite all his protestations, is endeavoring to turn this country into a theocracy. His bias is quite blatent.
I saw his post where he gives his list of "possible reasons" why people voted for Democrats in the last election. They are, of course intended to sound like no sane person would ever vote for anyone but a hard-line Republican. In reality, of course people are not so tethered to the political parties, especially since one has to hold one's nose to vote. The Republicans lost in the last election because the president launched a war in Iraq for personal reasons, the economy tanked on Republican watch (not that they had any control over it, but they were in power and got the blame) and let us not forget the "majority of the majority" nonsense. Seriously, it got to a point where lobbyists were told that, if they weren't acting to try to get every seat in Congress under Republican control, their proposals wouldn't be heard. And neither party can be trusted with that kind of power. So the people voted the crooks out. Sure, they were replaced with a new set of crooks. But the action was (more or less) rational.