As I am sure you know, there is a rapidly congealing MSM meme that in last week’s first presidential debate, Mitt Romney shook himself loose of his reactionary party and revealed himself as the Massachusetts Moderate he’s always really been, just in time to snatch victory from the jaws of defeat.

I issued a strong protest against this meme on Friday, noting that with the arguable exception of points of emphasis on his convoluted tax proposal, and perhaps a howlingly incredible pledge to govern in a bipartisan manner, Romney didn’t move an inch in the debate. But if you don’t believe me, here’s Ezra Klein today:

Romney promised he wouldn’t raise a cent in taxes to retire a debt far larger than the one George H. W. Bush faced. He had nothing at all to say about climate change. He said health-care reform should proceed state-by-state, but he proposed Medicaid cuts that would make it impossible for any other states to do what Massachusetts did in 2006. He offered no short-term help to the unemployed, proposing instead to concentrate on long-term initiatives like energy independence. He again proclaimed allegiance to his budget promises, which would mean a 40 percent cut in everything but Medicare, Social Security and defense spending by 2016, though the only specific cut he mentioned was to PBS.

The list of Mitt’s moderate moments, meanwhile, goes something like this. “Regulation is essential,” he said. “You can’t have a free market work if you don’t have regulation.” He also swore fealty to Medicare — though he wants to move it into a premium support system in which seniors use a capped voucher to choose between Medicare and private insurers. He forswore any intention to give tax cuts to the rich, or really to anybody, though he didn’t explain how that would work given his promise to cut tax rates by 20 percent across-the-board.

As the Republican party has moved to the right in recent years, so too has our standard for what counts as a moderate Republican. These days, if you’re willing to admit that President Obama was probably born in the United States, that the U.S. Treasury probably shouldn’t default on its debts, and that someone, somewhere, might occasionally have to pay taxes, then congratulations, you’re a moderate Republican!

Ezra goes on to say that the reason today’s “moderate Republican” is yesterday’s “arch-conservative” is that the former fears a right-wing primary challenge more than the loss of potential voters outside “the base.” That’s true as far as it goes, and is particularly true with respect to Mitt Romney, who had to prove his fealty to The Cause to win the nomination over a hilariously inept set of nomination rivals, even as he successfully challenged their own orthodoxy.

But at a deeper level, the new, strange definition of “moderation” in the GOP is the product of three big developments: (a) the culmination of the slow but steady conquest of conservative media, grass-roots Republicans all across the country (not just, as in the past, the South and West), and key elements of the National Party Establishment by the same “movement conservative” ideology that undergird Barry Goldwater’s premature revolution in 1964; (b) a radicalization of the conservative movement itself in the wake of Barack Obama’s election (dramatized by the rise of the Tea Party Movement, itself nothing more than the same old conservative activists wearing tri-corner hats), reinforced by the 2010 midterm victory; and (c) the acceptance by the MSM (and perhaps more than a few low-information “swing” voters) of a definition of “moderation” that is entirely relative to the rightward lurch of the GOP and is now based on the kind of empty rhetorical gestures Romney shrewdly made in Denver.

All three trends were pretty accurately plotted by Jacob Hacker and Paul Pierson in their 2006 book Off Center. You can argue all day long about the complicity of Democrats in this phenomenon, and/or what they might have done to forestall or at least expose it. But at the moment, it’s become urgent for the Obama campaign to get back to what it was trying with considerable success to accomplish during the Charlotte convention before Mitt’s “Boca Moment” misled it into thinking Romney had definitively painted himself into a corner: draw constant attention to the actual GOP agenda, as reflected in the Ryan Budget and a host of blood oaths to wealthy donors and the Christian Right. Joe Biden will have a fresh opportunity to do that in this week’s debate with the real leader of the GOP, Ryan himself. And for all the talk about how Biden just needs to be “aggressive” and “populist” on Thursday night, some simple and pointed truth-telling needs to be in the mix.