For the last three months, Rick Santorum and Newt Gingrich have been repeating the same argument against Mitt Romney: He’s a moderate, and a moderate Republican can’t win the White House. Naturally, given Gingrich’s stature as a historian, the critique dredges up memories of campaigns past. “We tried a moderate in 1996, and he couldn’t debate Bill Clinton effectively,” Gingrich said in January. “We tried a moderate in 2008. He couldn’t debate Barack Obama effectively and lost.” Santorum, too, has invoked the gruesome specters of Bob Dole and John McCain. “Look at the races in the last 30 years,” he chimed in last month. “[When] we nominated a moderate: McCain, Dole, Gerald Ford. When George [H.W.] Bush ran for re-election back in 1992 … [They] all lost.”

The argument is incredibly self-serving—both men invariably cast themselves as Reagan-esque antidotes to Romney’s flaccid centrism. It’s also highly counterintuitive: As much as conservatives like to believe the average American aligns with their worldview, the country is clearly far, far more progressive than the typical Tea Partier. (Not surprisingly, polls have consistently shown Romney faring much better against Barack Obama than either rival.) But that doesn’t make the argument untrue! Indeed, if the last week or so has taught us anything, it’s that Romney’s reputation for moderation could be a major liability against Obama.

Not, mind you, for the reasons Gingrich and Santorum posit. Their version of the argument is the one you always hear from hardliners—that voters punish political mimicry. “If it’s a difference between ... Tweedledum and Tweedledee … this country is going to probably going to stick with the person they know,” Santorum explained. “We need to have a sharp contrast. Someone who paints a very different vision for America.” This makes little sense, except perhaps when it comes to health care, which is genuinely unpopular and which Romney’s record leaves him hard-pressed to exploit. Beyond that, does anyone believe a candidate touting Mullah Santorum's views on reproductive rights and homosexuality would do better on Election Day?

In fact, the case for a conservative nominee is basically the opposite of the one Gingrich and Santorum make: The reason conservatives have traditionally done better in presidential elections is that they have the luxury of running to the center. Consider, for example, George W. Bush. Precisely because no one doubted his conservative credentials—the man’s favorite philosopher was Jesus Christ, for God’s sake!—Bush could style himself a minority-loving, compassion-exuding moderate without worrying that conservative mau-mau-ers might pounce at any moment. Recall that it was Bush who, back in October of 1999, criticized House Republicans for trying to “balance their budget on the backs of the poor.”

Dole, by contrast, was dogged throughout the primaries by the charge that he was insufficiently conservative. Phil Gramm and Steve Forbes spent tens of millions of dollars driving home the point, and Pat Buchanan used every minute of his free air time to reinforce it. The upshot was constant anxiety within the Dole camp about his conservative bona fides, culminating in the selection of supply-sider Jack Kemp as his running mate and the embrace of a perfectly ludicrous tax plan. (Though one, I should add, that’s become mainstream in today’s Republican Party.) Likewise, conservatives never got over their suspicions of McCain on everything from campaign finance reform to immigration. When it came time to fill out his ticket, he too lurched far to the right.