‘PRECONDITIONS’…. The new McCain campaign ad argues that Obama will negotiate with Ahmadinejad about the elimination of Israel and the withdrawal of all U.S. troops from every country in the Middle East. It is, as Andrew Sullivan accurately noted, “disgusting, stupid, inflammatory and, in its use of Arabic-sounding music, bigoted.”

I was planning to break it down and tear it apart, but it looks like Joe Klein beat me to it.

There is so much desperate, crapulous spew from the McCain campaign right now that it’s hard to keep track of it all — but this ad, via Andrew Sullivan, marks some sort of low. Yet again — in a last, desperate attempt to scare the elderly Jews of Florida — McCain posits Mahmoud Ahmadinejad as the “leader” of Iran, even though he has no control over Iranian foreign or military policy. (Ayatullah Ali Khamenei is the guy in charge in Iran, which is why they call him — you guessed it — the Supreme Leader.) Yet again, McCain brings up the notion of “preconditions,” only now the preconditions are Ahmadinejad’s: namely, that the U.S. would have to leave the Middle East before he’d be willing to talk.

It’s all inflammatory nonsense, of course. Obama has said that he would meet with the Iranian leadership without “preconditions” — namely, the Bush Administration requirement that the Iranians stop processing uranium. Of course, the Bush Administration doesn’t seem so set on that precondition anymore, either. Again, this is a purposeful effort to mislead on Obama’s actual position: he would begin lower-level negotiations with the Iranians, and see how much progress could be made. That is a position supported by many of McCain’s own diplomatic supporters.

But that’s not really what this is all about: this ad — with its Middle Eastern music — is all about implying that Obama isn’t one of us, that he’s one of them. It is shameful, in the extreme. It’s also really bad policy.

I’d just add one tangential thought to this. There’s going to come a point, probably in a couple of weeks, at which John McCain is going to express some kind of “regret” for just how disgusting his campaign became. He’ll do this if he wins (hoping to generate some pre-inauguration goodwill), and he’ll do this is he loses (hoping to improve his tarnished and discredited legacy). McCain will probably say, with apparent sincerity, that things “got out of hand,” and he’s filled with “regret” for not having intervened before his campaign became too pathetic.

But an ad as offensive as this new one shouldn’t be forgotten, or forgiven. McCain, under pressure, is putting his character on the line for all to see, and post hoc remorse should be irrelevant. McCain had a choice — lose his honor or lose the election. Whether he ends up losing both remains to be seen, but either way, McCain did not choose wisely.

Steve Benen

Follow Steve on Twitter @stevebenen. Steve Benen is a producer at MSNBC's The Rachel Maddow Show. He was the principal contributor to the Washington Monthly's Political Animal blog from August 2008 until January 2012.