To their fans, the comeback drives of first Mark Sanford and now Anthony Weiner are happy signs that the American electorate is willing to embrace redemption. To their detractors, such ambitions are evidence that shame has lost its rightful place on the roster of politically effective motivators.

Either way, their stories are absolutely fascinating to the people who watched them launch their congressional careers in the 1990s, when their futures seemed almost limitless, then crash because they suffered from a pair of all-too-familiar politicians’ problems: believing in their own personal infallibility and not believing that the cover-up is almost always a bigger problem than the transgression.

Beyond the facts that both were driven into the political wilderness by self-generated sex scandals, both have been publicly contrite for a couple of years now and that both kept plenty of campaign cash in reserve for the moments at hand, the Sanford and Weiner stories have plenty of important differences. What makes the current comparisons doubly interesting is that those distinctions suggest the inverse of what’s likely to happen.

A review of facts would make you think Sanford, the conservative Republican, has much less of a shot at reclaiming his old House seat in South Carolina than the liberal Democrat Weiner has at realizing his lifelong dream of becoming mayor of New York City. Actually, the opposite is more the case. Sanford is the clear if not in-the-clear frontrunner in his May 7 special election, but if Weiner makes a late entry into the crowded mayoral primary field, he would be an underdog to get beyond the first round on Sept. 10 and into a runoff.

Both men were at political pinnacles when they allowed their libidos to get the best of them. Sanford remained popular at the midpoint of his second gubernatorial term in 2009, when he hid his whereabouts for six days to pursue a secret extramarital affair in Argentina. Weiner had become one of the most prominent spokesmen for House Democrats in 2011, when he denied for weeks that it was his pectorals and groin pictured in a series of texts, Tweets and emails to a variety of women.

The first difference, obviously, is that Sanford eventually admitted he was romancing a woman who was not his wife, while Weiner eventually admitted that he was sexting women he hardly knew at all.

Recovering from cuckolding your state’s first lady would seem to be a taller order than recovering from the ridicule of being revealed as a none-too-successful social media cad. But Sanford has done so, partly by becoming engaged to Maria Belén Chapur. And Weiner has not done so, partly because the combination of his surname and his behavior have been such a boon to the headline writers at the New York tabloids.

Another difference is in how the wives — each so accomplished and telegenic that it’s often said they’d make the better candidates  — reacted to their embarrassment. Jenny Sanford publicly and combatively pursued divorce. Huma Abedin privately and diligently pursued reconciliation. Being flamed by an ex-wife is undeniably a bigger campaign liability than being supported by a current wife.

Perhaps the most important differences seeming to favor Weiner’s chances for a comeback over Sanford’s, though, are their different means of political ascent, the different natures of their political base and the contrasting ways in which they sought to bring morality into the public square.

Sanford was a businessman at the vanguard of the “citizen politician” movement that helped the GOP take over the House in 1994. He railed often in his early career against the dangers of allowing hubris to envelop the career politicians. It would be reasonable to have expected the local GOP political establishment to have given him a wide berth long ago.

Weiner, by contrast, spent his whole adult life in politics; he was a congressional aide and city councilman before coming to Congress in 1998. And so it would be reasonable to suspect the city’s Democratic bosses would have stuck by him, in private if not in public.

Beyond that, the South Carolina coast is a reliably Republican place where the “culture wars” aren’t close, where old-line Christian virtues are still in vogue and where Sanford was eager to cultivate all of that with discussions of his own social conservatism. Queens is more Democratic, socially liberal and Jewish, and Weiner never had all that much to say in those neighborhoods about the hot button morality issues of the day. In short, Sanford was much more obviously vulnerable to charges of hypocrisy than was Weiner.

And yet it’s much more likely that Sanford can hike all the way back from the Appalachian Trail than that Weiner will be allowed in the locker room of the House gym. The would-be-congressman-again seems likelier to find patron saints in Newt Gingrich and David Vitter than the would-be mayor will in Bill Clinton.

The “god of second chances” may be a bipartisan deity — yet without sufficient power to conquer the phenomenon of all politics being local.