Ahead of Saturday night’s GOP debate, a social-issues-focused forum hosted by two conservative Christian groups, one of the groups’ directors announced that Herman Cain would not be asked about allegations from four women that he sexually assaulted them. “Every person in every press outlet that I’m aware of wants to get to Herman Cain on these questions about sexual harassment from years ago and they’re having ample opportunity to do that,” said Tom Minnery, the executive director of CitizenLink, the political arm of Focus on the Family.

Sure enough, the allegations weren’t mentioned. And in keeping with the event’s insistence on overlooking past sexual and moral behavior, Newt Gingrich delivered righteous lectures on conservative values without being asked about his hypocritical business deals, cheating on two of his wives, or the fact that he’s been married three times.

To anyone outside the evangelical conservative bubble—and probably even a few inside it—this was a jarring contradiction. How could the forum’s self-described “pro-family” organizers, who grilled the candidates on exactly how they plan to dismantle abortion and gay marriage, have so little interest in these unsettling episodes in their candidates’ backgrounds? How could they be content with vague questions about “what you’ve learned from your mistakes,” and with equally vague responses that evaded the questions on everyone’s minds?

The first reason was clear in Minnery’s explanation of why Cain would not be asked tough questions about his alleged sex crimes. “I suspect that the candidates are as frustrated as those of us in the viewing audience with ‘gotcha’ questions,” he said. It’s hard to overstate the religious right’s media persecution complex: they hold the entertainment media responsible for introducing sexual permissiveness, the social acceptance of gay marriage, and what they see as general cultural indecency; they believe the political media systematically portrays conservatives and believers as provincial idiots. They instantly identifiy with others they believe are under similar attack, sometimes to the point that no amount of evidence will convince them the media is following a legitimate story. Thus Cain is automatically innocent, and there must be something good about Gingrich if the media dislike him enough to bring up his divorces.

It’s not suprising, then, that Gingrich has slowly won over conservative voters by portraying himself as under relentless attack by media debate moderators. But Saturday night, he executed a move even more important for securing evangelical absolution: an emotional account of realizing his weakness and sin and submitting to God. Gingrich described an unspecified time when he was at the height of his success but still felt “hollow,” and “had precisely the symptoms of somebody who was collapsing from under this weight.” Gingrich said that experience produced “a great deal of pain, some of which I have caused others, which I regret deeply.” He sought “reconciliation” from God and “had to recognize how limited I was and how much I had to depend on Him.”

Personal conversion, and re-conversion after “backsliding,” are the core of evangelical faith. Virtually every evangelical Christian, no matter how squeaky-clean their life may have been, has a “testimony” about the moment they became aware of their sin and need of a savior. Nearly every candidate gave his or her “testimony” Saturday night. These can seem almost comically contrived, like Rick Santorum’s riff on realizing he had mentally devalued his diseased infant daughter in the same manner as women who end their late-term pregnancies. But the testimonies of serious sinners—say, thrice-married serial adulterers—can have a particularly powerful effect on believers. Radical “come to Jesus” experiences reinforce evangelical mythology about everyone else in the world being miserable and depressed without God, a belief reiterated Saturday night by moderator Frank Luntz. They also connect with evangelicals’ unique commitment to forgiveness: except in a few extreme cases, true repentance requires a believer to start over with a spouse, friend, or leader who may have wronged them in a fashion most people would find unforgivable.

But when it comes to politics, the forgiveness is curiously one-sided. Bill Clinton earned evangelicals’ permanent moral revulsion for sexual misbehavior no worse than Gingrich’s—he stayed married!—and much less troubling than the crimes of which Cain is accused. This selective obsession with integrity is the open secret of evangelical politics: a politically-engaged evangelical who is not also a Republican partisan is hard to find.

Despite evangelical politicians’ insistence that they are “Christians, conservatives and Republicans, in that order,” there are few significant differences between the three. Evangelicals’ relationship with the GOP is no longer just the marriage of convenience it once was; the two now define and depend on one another in fundamental ways. The radical, reactionary bent of the current Republican Party is grounded in decades of mythmaking and resentment in the evangelical subculture. In turn, evangelicals have absorbed the anti-tax, deregulatory ideology of the party of the rich.

The near-complete identification with Republican politics has led to widespread hand-wringing about the hyper-politicization of the Christian gospel, and even some prominent evangelical leaders have expressed their regret. In 2009, disgraced Nixon aide-turned-Christian-minister Chuck Colson told Time, “We made a big mistake in the ‘80s by politicizing the Gospel. … We [thought] that we could solve the deteriorating moral state of our culture by electing good guys. That’s nonsense.”

Though many evangelicals now pay lip service to that critique, they have yet to find a replacement for the political wars they’ve spent a generation fighting. And with the smell of blood thick in the 2012 air, they have little incentive to avoid their familiar spot on the Republican side of the battlefield, no matter who ends up leading the charge. In 2008, conservative pastors urged them to hold their noses and vote for John McCain, even though he had called the religious right “agents of intolerance,” was slippery on abortion, and had abandoned a badly-injured wife. If the candidate evangelicals believe can take Obama down next year has dumped two wives or harassed four employees? That’s just politics, and they long ago accepted that it is a dirty fight.