It says something about the state of the Republican presidential contest that a candidate with a history of appealing to independents and an admirable record of center-right governance is out 25 weeks before the first Republican vote is cast.

Tim Pawlenty’s problems were not purely ideological. Midwesterners sometimes go to great lengths to hide their charisma. And Pawlenty seemed uncertain of how to exploit Mitt Romney’s past crimes against conservatism, having committed a few of his own.

But Pawlenty’s explanation for his early exit rings true: “I brought a rational, established, credible strong record of results, but the audience was looking for something different.” Pawlenty’s campaign was a backhanded tribute to this shift. In normal times, a successful governor seeking promotion to the Oval Office would emphasize his or her cross-party appeal and domestic policy innovations as political virtues — the manner in which the last two presidents who served two terms ran and won. Instead, Pawlenty attempted to adopt Tea Party themes and outrage, which hung on him like a poorly fitting suit.

Pawlenty ended up with an authenticity problem — symbolized by his sudden, Damascus Road unconversion on a human role in climate disruption. Any Republican who has won tough elections in ideologically diverse states — say, Wisconsin or Massachusetts — will have a few heresies to renounce or defend. RomneyCare is exhibit one. But Mitt Romney’s ideological overhaul is not as recent as Pawlenty’s. And compared with his behavior in the last nomination cycle, Romney seems less panting in his desire to please, making him a more confident candidate.

Hopefuls from Texas or the 6th Congressional District of Minnesota face fewer immediate authenticity problems. Their constituents more closely resemble the voters who will choose the Republican nominee. Michele Bachmann gained a national platform by winning 159,476 votes in the most Republican House district in her state. Just as sexual purity is less impressive in the absence of opportunity, ideological purity comes more easily when there is little political need to appeal across ideological lines. As governor of Minnesota, Pawlenty was required to build diverse political coalitions. Bachmann has made fewer compromises, in part, because she has held fewer responsibilities.

On the face of it, Texas Gov. Rick Perry has his own authenticity problem. As late as 1988, Perry was a Democrat and Al Gore’s Texas state chairman. But Gore, it is now difficult to remember, was then viewed as a Southern centrist. And a conservative Democrat in Texas can be as conservative as a Republican anywhere else. Perry’s transition to the Republican Party was the political story of much of the South. Perry is not an ideological turncoat; he is the embodiment of a trend that transformed American politics.

Yet Perry, in his own way, demonstrates the complexities of governing that a member of the House is never forced to experience. Perry signed an executive order requiring that girls entering the sixth grade be vaccinated against human papillomavirus to prevent some types of cervical cancer — a perfectly rational public health measure opposed by some conservatives. More controversially, Perry supported a bill to give in-state tuition to the children of illegal immigrants. This position may have resulted from personal conviction. It certainly reflected a political reality in Texas, where Republican success has involved outreach to Hispanic voters. “We must say to every Texas child learning in a Texas classroom,” Perry argued, “ ‘We don’t care where you come from, but where you are going, and we are going to do everything we can to help you get there.’ And that vision must include the children of undocumented workers.”

So three prominent Republican governors can be accused by conservative activists of ideological impurity — Pawlenty on climate, Romney on health care and Perry on immigration. Yet maybe this is not a scandal but a lesson. Successful governors accommodate a diverse electorate within the bounds of their convictions. They build governing coalitions through unexpected outreach. And sometimes they follow their convictions into ideological unpredictability. These are not indications of apostasy but signs of electoral skill and strength.

In the general election, these virtues are not optional. Even the most committed conservative nominee will shift his or her tone on some issues that brought them to prominence — as Bachmann has already begun to do on homosexuality. And as Perry eventually will need to do in order to expand his message beyond the largely negative themes of the 10th Amendment and climate-change skepticism.

In presidential politics, conviction is important, but ideological purity is overrated.

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