By all accounts, Barack Obama is quite far along in his deliberations over a running mate. If he hasn't already made his choice, it's down to a tiny handfull of people. The time for suggesting new names, in other words, has long since passed. But with Michigan and its pivotal role in the election on my mind, I can't help but throw out another possibility, one so seemingly ideal I'm surprised we haven't heard more about him already: Senator Carl Levin.

What woud Levin bring to the ticket? First, and most important, he's qualified both to help the president govern and, in an emergency, to become commander-in-chief himself. A graduate of Swarthmore and Harvard Law School, Levin has a resume in public life that dates back to the 1960s, when he was state attorney general. He became a U.S. Senator in 1978 and since that time has built a reputation as one of its most effective members.

Levin has consistently championed the cause of good government, pushing to close tax loopholes and expose corrupt contracting practices. (Among the measures credited to him are the Whistleblower Protection Act.) He's also become one of the Senate's most knowledgeabe, and trusted, voices on military and national security affairs. As chairman of the Senate Armed Services Committee, he commands respect from both the military brass and his Republican senate colleagues. He's demonstrated consistently sharp judgment, too: Like Obama, he was against the war from the start. And he justified that opposition by warning, correctly, that the evidence of Iraq's threat was far too thin.

The potential drawbacks to Levin are all political, starting with the fact that he's been around Washington for a long time. But his credentials as a reformer are pretty impeccable; that might help blunt the Washington charge. In appearance and manner, Levin conveys the image of a rumpled, wise, but friendly old man--which is rather different than the blow-dried, vapid, mechanical impression more stereotypical politicians--including, ahem, this guy--tend to make.

Wouldn't a black-Jewish ticket be politically deadly? I'm not so sure. If anything, a Jewish running mate could actually help Obama's candidacy both in suburban Detroit (where Levin is insanely popular) and South Florida, the communities that may well hold the key to their respective states. Meanwhile, Levin has always shown a strong ability to won over blue-collar voters, as any successful Michigan politician must. (It probably goes without saying, but he's also a favorite of the unions.)

One final thing: Levin, who appears regularly the Sunday shows, is also a terrific surrogate. He goes after opponents aggressively--and, based on what I've seen, cleverly. If his grandfatherly way means he's not always the most electric speaker, it also lets him deliver his attacks without seeming nasty.

I know, I know--it's way too late for this sort of thing. If we haven't heard about Levin by now, we're not going to see him on the ticket. But surely Obama will want to be pondering something while he's taking that vacation next week. Why not this?

--Jonathan Cohn