In the GOP’s whack-a-mole primary process, Newt Gingrich is about to get thumped by conservatives.

The cause is likely to be climate policy. It is not only that Gingrich appeared next to Nancy Pelosi in a 2008 commercial calling for “action to address climate change.” A year earlier, Gingrich argued, “The evidence is sufficient that we should move toward the most effective possible steps to reduce carbon-loading in the atmosphere.” To that end, he supported “mandatory carbon caps combined with a trading system, much like we did with sulfur.”

At the time, Gingrich’s position was not unique. John McCain had been the Senate sponsor of cap-and-trade legislation. His primary GOP opponents in the 2008 presidential campaign, Mike Huckabee and Mitt Romney, had endorsed greenhouse gas limits in various forms. When Tim Pawlenty was criticized for similar views this year, he noted, “Everybody in the race — at least the big names in the race — embraced climate change or cap-and-trade at one point or another. Every one of us.”

There is a reason for such mass heresy: because the case once made by Gingrich and the others is perfectly reasonable. Conservatives have been open to market-oriented restrictions on pollution since Milton Friedman talked of “effluent taxes.” Recent studies, using increasingly refined methodologies, have confirmed a long-term rise in global temperatures and made a strong case for the contributing role of carbon emissions. In addition, many national security conservatives are disturbed by the massive U.S. payments to hostile, oil-producing nations.

But Gingrich, in the manner of Cultural Revolution self-criticism, has now called his appearance with Pelosi the “dumbest single thing I’ve done in recent years.” Some conservatives may dispute this claim, arguing that Gingrich’s previous support for the individual health insurance mandate and the Medicare prescription drug benefit are rivals. (Never mind that Medicare now provides medicines to seniors at 41 percent less than was initially projected.)

It is now a familiar pattern — the scandal of sanity. Rick Perry is criticized for supporting discounted higher education for the children of undocumented workers, as though the ignorance of the innocent is an obviously superior policy option. Herman Cain is attacked for supporting a TARP bailout that prevented a national panic. “Owning a part of the major banks in America is not a bad thing,” wrote Cain in 2008. “We could make a profit while solving a problem.” Which is precisely what happened. For all its (considerable) flaws, Mitt Romney’s Massachusetts health reform was based on ideas that originated in conservative think tanks.

There is room for debate on all these issues. Cap-and-trade may be an innovative, market-oriented solution or an easily gamed mess. Romneycare may be a good idea badly applied or an approach doomed to failure. But these are not the arguments we’ve seen. Instead, candidates are accused of political heresy. Then they apologize — some eagerly, others reluctantly. Movement conservatives have created a box of orthodoxy so small that even the most conservative candidates must engage in undignified contortions just to fit.

Some of this is just the nature of primaries, in which audiences applaud for purity. But there are other factors. Over the past few decades, the GOP has become a more conservative party. The development of self-consciously conservative media — on radio, cable and the Internet — has provided a welcome alternative to the bias of the mainstream media. It has also simplified many public debates into a contest of ideological teams — a tendency shared by self-consciously liberal media. Candidates, pundits and voters are called to join one side or the other, doing nothing that will give comfort to the enemy. But ideological conformity easily becomes cultural isolation — the development of assumptions, language and views disconnected from the broad middle of American life.

Many political activists have adopted a form of fundamentalism: the belief that a return to power can be achieved only by a return to purity. This is particularly unproductive during a presidential primary. It narrows the range of qualifications — elevating fealty above other, important public virtues such as stable judgment, competence, relevant experience and integrity.

And this approach makes for bad politics. There is a reason that the purest candidates are often not the strongest candidates. Appealing, successful politicians have usually built unexpected governing coalitions, engaged in creative ideological outreach and shown intellectual independence.

A political party that is serious about winning does not punish candidates for their virtues.

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