A South Carolina Republican primary for an open congressional seat leaves former South Carolina Gov. Mark Sanford the favorite to win an April 2 GOP runoff.

Sanford’s return to politics, after an extramarital affair and elaborate lies to cover it up, has prompted discussion about how unlikely such a comeback is for a staunch Republican in a party steeped in so-called “family values.”

On the Today show (3/19/13), NBC News correspondent Kelly O’Donnell called Sanford’s effort “a chance for an unlikley comeback…despite a spectacular fall from grace in 2009.” ABC News online reporter Chris Good (3/20/13) declared that the primary vote was Sanford’s “first test in what might be a political comeback for the ages.” As early as January (1/16/13), Washington Post correspondent Sean Sullivan wrote of Sanford’s “unlikely political comeback after a dramatic fall from public grace four years ago.” Sanford was widely quoted saying he believed in a “God of second chances.”

A Salon piece (“Why Is Sanford’s Comeback Easier Than Others?,” 3/20/13) that attempted to explain why Sanford’s reentry seemed to be going smoothly asked, “What is it about Sanford that made him so forgivable, while politicians like Anthony Weiner and Eliot Spitzer have not been?” The piece finds a culprit in the media culture in New York, where Spitzer and Weiner fell from grace as, respectively, the governor and a U.S. congressmember: “The tabloid culture is so pervasive and persistent that it made it much harder for Spitzer and Weiner to survive after their scandals broke, and to rehabilitate themselves for a potential comeback.”

Salon‘s Jillian Rayfield quotes New York political consultant Risa Heller, who says with the media landscape dominated by the tabloid New York Post and Daily News, “New York is a different kind of place with different kind of media, and it’s just not like there anywhere else.”

But this media discussion misunderstands the rules of political banishment and redemption as they apply to U.S. politics generally, and specifically to Sanford’s comeback. The journalists make the mistake of assuming that since the GOP spends so much time preaching “family values” and “social conservatism,” Republican pols who violate these preachments must pay a greater price than less moralistic Democrats.

This is not true. Republicans have traditionally paid a lesser price to reenter politics following a sex scandals.

That’s why thrice-married serial philanderer New Gingrich could become a respectable 2012 primary candidate in the Bible-thumping ranks of the family party. And why married prostitute-patron and political strategist Dick Morris could become one of the most frequently appearing guests on Fox News (along with Gingrich)–sitting next to hosts and moral scolds such as Bill O’Reilly (who settled a multi-million-dollar sexual harassment case) and Sean Hannity, who seems to specialize in redeeming disgraced family values politicians like Gingrich, Morris and Sen. David Vitter, whose political career went uninterrupted after he admitted to consorting with prostitutes (Extra!, 1/09).

Former New York City Mayor Rudolf Giuliani was quickly forgiven for publicly cheating on his second wife with the woman who would become his third; and who even recalls that Sen. John McCain did the same with his first wife with the woman who would become his second?

Contrast these relatively thriving political careers with those of Democrats like Spitzer and Wiener, whose careers are truly dead, or the even more dramatic falls of former Democratic presidential candidates John Edwards and Gary Hart, whose political fortunes are really most sincerely dead.

So it’s not about New York’s tabloid media. But Salon does hit on one clue that helps explain the double standard when it quotes political consultant Chip Felkel explaining one reason for Sanford’s smooth comeback: “In the South, where people certainly believe in forgiveness, his ads were compelling in terms of him getting a second chance.”

So, it’s forgiveness, or “the god of second chances,” as Sanford put it. But you have to understand that the second chances are only available to the believers, those who belong to the “family values” tribe.

This is why, as far as marital fidelity was concerned, media seemed to see McCain as fit enough to be president, while Edwards was rendered a political nonperson. And why Gingrich, with no apparent shame, could lead GOP forces to impeach President Bill Clinton over his efforts to conceal an extramarital affair. What seems to be most important for social conservatives and Republicans is what they profess, not what they practice.

And this is why Hannity, while regularly surrounding himself with philanders Gingrich, Giuliani, Morris and Vitter, judged that John Edwards’ failings made him unfit for public service (Hannity & Colmes, 8/12/08): “If you can’t keep the promise to your family, can’t keep your promise to your wife, you’re having an affair, you’re lying about the affair repeatedly, why should the American people trust you when you say you’re not going to lie to them?”

And why, two years after Sanford’s scandal, Hannity praised him in a full hour-long interview as a “staunch Christian conservative” who was “Tea Party before Tea Party” (Hannity, 8/5/11). Hannity asked Sanford about his affair and policy, and pressed the former governor to announce if would be making a political comeback: “You say that you are probably more prepared now to be a leader in a sense, there’s been a lot of talk about maybe you reentering the political world, I’m jumping ahead, a little bit. Are you considering that?”

Mark Sanford’s comeback is only unlikely, or surprisingly smooth, if one doesn’t understand the double standard–the culture of permissiveness, if you will–that operates in the media and the Republican Party when it comes to conservatives’ moral failings.