It’s been about five days since Rep. Vance McAllister, a self-described “faith and family” Louisiana Republican, was caught on video in an extra-marital dalliance with a staffer and donor. He issued a statement acknowledging that he’d “fallen short” and is “asking for forgiveness.”

As of yesterday, many of McAllister’s fellow Republicans apparently aren’t in a forgiving mood

On Thursday, Louisiana Gov. Bobby Jindal amped up the pressure on the so-called “kissing congressman” to step down, releasing a statement calling McAllister’s behavior “an embarrassment.” […] Earlier in the day, the chairman of Louisiana’s Republican Party asked for McAllister to step down as well – and he didn’t mince words while doing it. “Mr. McAllister’s extreme hypocrisy is an example of why ordinary people are fed up with politics,” Louisiana Republican Party Chairman Roger Villere Jr. said in a statement. “A breach of trust of this magnitude can only be rectified by an immediate resignation. He has embarrassed our party, our state and the institution of Congress.”

By all appearances, McAllister is resisting these calls and hopes the controversy will blow over. While we wait to see if this strategy works, however, it’s become increasingly difficult to ignore a relevant question: can anyone explain why McAllister’s personal misdeeds are worse that of Sen. David Vitter’s (R)?

Or more to the point, why is it, exactly, that the same Louisiana Republicans calling for McAllister’s ouster are holding the congressman to an entirely different standard than the one applied to Vitter after the “family values” senator was caught having hired prostitutes?

The answer isn’t as mysterious as it may seem.

In 2007, after getting caught, Vitter acknowledged his “serious sin” with hookers, including an instance in which he arranged for a liaison while calling from the floor of Congress. The conservative Republican, who ran on a traditional-values platform, avoided prosecution because the statute of limitations had expired.

Republicans, including Bobby Jindal and state party chief Roger Villere, rallied to Vitter’s defense, and literally none of the senator’s GOP colleagues publicly called for his resignation. Why not? In part because Vitter had established deep party ties, in part because Louisiana’s governor at the time was a Democrat – and if the scandal-plagued senator stepped down, then-Gov. Kathleen Blanco likely would have appointed a Democratic replacement.

Republicans, in other words, had a strong incentive to look the other way, despite the seriousness of Vitter’s sex scandal – an incentive that does not apply to Vance McAllister.

But going one step further, let’s also not forget that when McAllister was elected just six months ago in a special election, he was running against a state senator that the party establishment loved . Neil Riser had received endorsements from nearly all of Louisiana’s Republican congressional delegation, the NRA, and House Majority Leader Eric Cantor (R-Va.), but he lost anyway to McAllister, a first-time candidate.

Party insiders were not pleased, and his messy personal life suddenly offers them a chance to smack him down.

In other words, Vitter could take the heat thanks in part to the intra-party relationships he’d cultivated over the course of many years. Indeed, now the senator is running for governor, and his past with prostitutes won’t derail his candidacy at all. McAllister has no comparable ties, so a video-taped kiss has brought out the long knives from his ostensible allies.