This wasn’t the vote on the final bill (that comes Wednesday), merely the vote to proceed to consideration of it, but it’s still significant as a barometer of how many Dems might be willing to defect next week. Result: 236-181, with just four Blue Dogs joining Republicans in the majority. How can that be, you ask, when 34 Dems voted no on ObamaCare back in March? Well, remember, most of that herd of 34 was culled by voters in November, leaving just 13 survivors to vote on this bill. (There’s one “achievement” you won’t hear Pelosi boast about.) And of those 13, most are now in a position where they have more to fear from angry liberals challenging them in a primary than from conservatives coming after them in the general. The Daily Caller explains:

So far, only two House Democrats who voted against the health-care bill in March have said they’ll support the full repeal: Rep. Mike Ross of Arkansas and Rep. Dan Boren of Oklahoma. A few others are uncommitted and could end up voting for repeal.

The political calculus for many of these House Democrats is fairly simple. First, they are now in a general election cycle where more voters will participate in their primary election because of the president’s presence on the ballot.

Obama’s base support will also bring more young and minority voters to the polls who will be sympathetic to the kind of political attack ad that could be run against House Democrats in a primary challenge, hitting them for opposing the parts of the bill that make for political hay.

“Voting for repeal opens the door to a primary challenge from their left. And while they may win it, it’s something they don’t want to have to deal with,” said a senior House Democratic leadership aide.

Ross and Boren were two of the four Dems who voted yes today; the others were Larry Kissell and Mike McIntyre. All four voted no back in March, and all four had a surprisingly easy time against the GOP in the general election last November notwithstanding the big red wave breaking across the country. Boren won by 13 points, Ross by 17, Kissell by nine, and McIntyre by eight. The thinking here, I assume, is that liberals won’t risk challenging southern Democrats who seem to have a lock on their seats; they’re too rare and valuable these days. If they’re going to go after someone, better to go after a Jason Altmire who won with only 51 percent in November and could have another tough run ahead in 2012. Liberals could knock him out in the primary and then, with Obama base voters turning out in the general, win back the seat with a more liberal Democratic nominee. No wonder, then, that Altmire voted no today after voting no on O-Care back in March whereas Boren et al. felt comfortable sticking it to the left by voting yes on repeal.

The new line from vulnerable Blue Dogs (including Joe Manchin) is that they’ll vote to repeal the bad parts of the bill but not the whole thing. Which is a neat trick, since retaining the good parts — like the coverage for people with preexisting conditions — while jettisoning the bad parts that pay for it — like the mandate — would produce a total clusterfark of unintended economic consequences. But then, the “repeal some but not all” position isn’t a serious policy idea, it’s a cop out by centrist Dems looking to please liberals and conservatives at the same time. And in fairness, it might work: Not only is the country roughly evenly split on repeal, but as Geraghty notes, there’s a surprisingly large contingent within each party that breaks from the party line about the law. Among Dems, just 64 percent want to keep it while 24 percent support repeal. With ambiguity like that, a squishy straddle has its appeal.

As companion reading, check out the memo from CBO that Philip Klein obtained showing that repeal would save $540 billion in spending. In reality, it would save a lot more than that given that the figures provided to CBO by Democrats have been gamed since the beginning to lowball the cost of ObamaCare over the first 10 years. If you believe there’s only $540 billion to be saved here, then you also believe that ObamaCare is a long-term revenue generator. And absolutely no one believes that. Except Nancy.