Rick Santorum’s impressive Super Tuesday showing—he won Tennessee, Oklahoma, and North Dakota, and lost Ohio by only a hair—compels political commentators to pretend that the nomination may still be up for grabs (when in fact the nominee will still almost certainly be Mitt Romney). That won’t last. In the next couple of days, discussion will turn to a more plausible scenario: Santorum, having shown himself to be popular with two constituencies that don’t cotton to Romney—evangelicals and Reagan Democrats—should get the number-two slot on the GOP presidential ticket.

Let me be the first to say that my motive, in rooting for this outcome, is deeply impure. I think a Romney-Santorum ticket would be a catastrophe for the GOP, because Santorum would scare the bejeezus out of political independents.

But Republicans might go for it anyway. Until recently it was widely assumed that Florida Senator Marco Rubio would be chosen number two in order to harvest the Hispanic vote. But Rubio’s damaged goods now, for two reasons:

1) We found out last month that he used to be a Mormon. It’s going to be hard enough to get evangelicals to vote for a one-Mormon ticket. A two-Mormon ticket would make what’s difficult well-nigh impossible.

2) Rubio was a principal sponsor of the recent contraception bill that the GOP leadership foolishly required its caucus to support. The bill would have allowed employers to refuse health insurance coverage for anything that they opposed on religious or ethical principles. That could be contraception; it could also be an appendectomy. Almost immediately Republican senators who let themselves get talked into supporting the bill started wondering if they’d blundered badly. The one Republican senator who voted against it decided she’d had enough of these bozos and announced she would not seek reelection, a choice that could imperil the GOP’s hopes of winning back the Senate. Romney himself said he opposed the bill until someone presumably told him it wouldn't be smart to contradict the Senate Republicans and he clarified that in fact he, ahem, supported it. Meanwhile, Romney’s doing so poorly among Latinos that it may no longer be worth trying to pick up a few points by choosing Rubio; better to take up the slack somewhere else.

Virginia Gov. Bob McDonnell was another plausible contender for number two until he made a fool of himself by supporting, and then abruptly backing away from, a proposed Virginia law that would have required women to subject themselves to a vaginal ultrasound probe before having an abortion. A predictable national uproar ensued. (The bill subsequently passed with a requirement for an ultrasound, but not necessarily one using the invasive probe. The dustup prompted an inspired Onion headline: “New Law Requires Women To Name Baby, Paint Nursery Before Having An Abortion.”)

Some will say that Santorum’s own opposition to contraception and abortion would similarly drag onto the GOP ticket unwanted controversies about intimate doings in Tierra del Fuego. Why alienate women from the party even further? Indeed, I myself am persuaded by this logic. That’s one reason why I’d like to see Romney choose Santorum. (I won’t even mention—shhhhh!—Santorum’s nutty views on education.)

But I think a lot of others will figure that Santorum, unlike Rubio and McDonnell, has proven himself to be a vote-getter, and that Romney desperately needs a running mate who can deliver the base. For Romney supporters, merely talking up the possibility, even if they hate the idea, might have the advantage of persuading Santorum to attack Romney less savagely in the remaining primaries—no small consideration for a candidate who’s struggling to close the sale. 

I feel in my bones that “Santorum For Veep” is the next political meme. It’s a terrible idea. Long may it live!

Update, 4:15: Ben Smith, who clearly didn’t get the memo, is talking up Ohio Sen. Rob Portman, former budget director under George W. Bush. No, no, no! The logic is that he got out the vote for Romney, but since Romney very nearly lost I’m nost sure how compelling that is. Plus Portman is kind of a Romney Mini-Me, entirely focused (as Romney is) on the economy. Plus, as Smith notes, the Dubya administration’s most memorable budget accomplishment was to take a small surplus and turn it into a gigantic deficit. I’m stickin’ with Santorum. Remember, in this primary race today’s high-concept gag is tomorrow’s headline!