Former South Carolina governor Mark Sanford is in the midst of a comeback effort. (Bruce Smith/Associated Press)

It only took a few years in the Senate woodshed, and now the political rehabilitation of Sen. David Vitter looks complete.

Our colleague Paul Kane Tuesday has Vitter — whose number showed up in the notorious black book of the “D.C. Madam,” causing the Louisiana Republican to admit before the cameras a “very serious sin” — back in the good graces of voters and colleagues alike.

But the senator’s reversal of fortune isn’t unique. There seems to be a boomlet of political comebacks underway. Maybe it has something to do with the onset of spring, the season of renewal?

Take Mark Sanford down in South Carolina. The former governor, who lied about hiking the Appalachian Trail while visiting his mistress in Argentina, has a legitimate shot at becoming the Republican candidate in the Palmetto State’s special congressional election. And in the three-makes-a-trend rule, there’s also former representative Anthony Weiner, who this month tested the waters with polls gauging the public’s willingness to put aside those photos of his undie-clad crotch he sent to a young woman who wasn’t his wife.

And for a bonus entry in the Gallery of Second Acts, the Long Island media is chewing over a possible political future for former representative Vito Fossella (he of the DUI arrest that led to revelations of a mistress and a love child).

Fossella’s response: “I don’t know what the future holds.” Last year, he told the Loop he “wouldn’t shut the door.” Sounds like a “put me in, coach!” to our jaded ears.

So how did three guys, whose collective scrapbook of embarrassment includes hookers, an Argentinian mistress, a secret family, naughty photos, and lies a-plenty, get second chances — or at least glimmers of hope?

Communications guru Lanny Davis says the price of admission is showing regret when caught. Not just crocodile tears, or the perfunctory script-reading that was Tiger Woods’s first public response to his sex scandal, Davis says, but the genuine article.

“If you show sincere, authentic pain and remorse, the public is willing to forgive,” he says. “It’s human.”

Which should give hope to former CIA Director David Petraeus, who was slated to give a speech Tuesday night — his first turn in the spotlight since he resigned his job amid a scandal over an extramarital affair with his biographer.