The thinking all along has been that they’ll fall a few votes short, that squishy Republicans like Snowe and red-state Democrats like McCaskill and Tester won’t dare tempt fate by backing an amnesty when they’re up in 2012. Don’t take failure for granted, though: The House made the bill a bit more appealing by scaling back some of the crappier provisions, and the collapse of the pork-packed omnibus spending bill last night gives centrists some added cover to gamble on this. They’ll be in a “historic” mindset anyway tomorrow if, as expected, the DADT repeal finally goes through, and it is, after all, just a week before Christmas. Maybe they’ll walk into the chamber tomorrow thinking: This year, why not give the gift of amnesty?

Jeff Sessions is circulating a list of 10 problems with the bill, but all you really need is Kaus’s closing argument. Pure and simple: “DREAM is all amnesty, no prevention.” If it goes through, border enforcers have handed over a key bargaining chip in some later comprehensive reform deal in return for a little bit of jack and a whole lot of squat.

Many DREAM opponents also want take care of these “kids” (or former kids) by making them legal. Mark Krikorian, the anti-amnesty advocate whom I cite most, wants to take care of them. Even Roy Beck of Numbers USA seems to want to take care of them. But there is a way to do it that minimizes the unwanted long-term side effects of encouraging future illegal immigration from parents now living in other countries (who’d understandably like their kids to be made Americans, too), which would set the stage for another amnesty, which in turn would build up a constituency for the next amnesty in a cycle that doesn’t seem to have any end point.

And there is a way to do it that maximizes those long-term effects, by maximizing the number of immigrants who would be covered by DREAM, by offering no effective way to combat fraudulent applications, by creating rules so complex they’ll collapse of the own weight, by passing the bill in a wave of ethnic passion and recklessly including no additional enforcement measures. That’s the bill they’ll vote on Saturday.

You’ve heard of “comprehensive” reform? DREAM is non-comprehensive reform. It doesn’t even have the basic enforcement provisions—employer sanctions and fancy new ID cards—that were part of the earlier, failed “comprehensive” bargain, which wasn’t a very good bargain (in part because nobody was sure the enforcement schemes wouldn’t be immediately undermined by lawsuits from the same organizations who supported “comprehensive” reform). DREAM is all amnesty, no prevention. Maybe that’s because its backers care about amnesty but not prevention.

Indeed they do, and none so much as their new self-appointed Pope. If you’re looking for offices to call, see Numbers USA’s list; fencesitters are highlighted in red, although you’re probably better off targeting Democrats rather than Republicans. The Maine sisters and Dick Lugar already know the stakes in their upcoming primaries only too well, so reminding them won’t achieve much. Bob Bennett and Voinovich are retiring, so pressure on them won’t work. Better to focus on McCaskill, Tester, Baucus, Kent Conrad, Ben Nelson, Mary Landrieu, Mark Pryor, and Kay Hagan — and, I guess, George LeMieux too, since he’s thinking of running again in Florida in 2012 and might be tempted to pander to Latino voters by switching to yes. Get cracking!