Rep. Vance McAllister is showing every sign he’s hunkering down in hopes of saving his nascent political life. But recent House history signals that it’s going to be a futile pursuit.

His troubles are unique in one respect — no member in modern history has seen his congressional career beset by scandal so quickly. It was just 137 days from when McAllister was sworn in to represent northeastern Louisiana, the Republican winner of a special election, to the release of grainy security camera footage of him in an 18-second lip lock with someone who is not his wife.

But Melissa Hixon Peacock is not simply a 33-year-old married woman caught canoodling with a 40-year-old congressman. Back when they were making out just before Christmas, and until Tuesday when she left the government payroll (whether voluntarily or not isn’t clear), she was his district scheduler. And that’s what places McAllister in what’s almost assuredly a non-survivable predicament.

In the past eight years, four other men of the House have been exposed for having, or seeming to seek, sexual relationships with congressional aides. None of them stayed in office longer than a couple of weeks.

Several members in the past few decades have (at least for a while) survived their sexual transgressions, substance abuse admissions, financial improprieties or other personal failings. But the punishment for dalliances with staffers has always been a swift political death penalty — no matter whether the behavior was by a Democrat or Republican, straight or gay, consensual or predatory, back home or on the Hill.

Twice in the past decade, Republicans resigned under intense pressure from House leadership that started as soon as their scandalous acts became public, as did one Democrat. In another instance, a freshman Democrat was soundly defeated days after his misbehavior came to light.

But in all those instances, the alternative to a rapid departure would have been to face one of the rarest consequences in today’s Congress: a formal investigation by the House Ethics Committee that would potentially expose more dirty laundry.

For patently obvious reasons of political propriety, the old aphorisms cautioning against interoffice dating — “Don’t get your honey where you get your money” — are heard at least as often in Congress as in the corporate world. But there is no formal prohibition against a member wooing (or trying to romance) a staffer. Instead, such behavior is governed by the catchall House rule requiring members to “conduct themselves at all times in a manner that reflects creditably on the House.”

If McAllister does not voluntarily cut short his own very brief time in Congress, odds are strong that his fellow Republicans won’t wait until November to see if the voters make the decision for him. Instead, some GOP lawmakers — worried their own careers might suffer from the scandal festering — can be counted on to ask Ethics to open an inquiry.

That’s what was about to happen in the most recent (publicized) case of a member and a staffer, the situation most analogous to the McAllister affair.

Mark Souder, a socially conservative and married Republican, and Tracy Jackson, a press aide in his Indiana office, were found by a park ranger in a compromising position in a parked car at an Indiana nature preserve. But it took until May 2010, six months after they were caught, for word to leak. That’s when Souder’s contemplation of a ninth term evaporated in days. One of his own Hoosier GOP congressional colleagues — Mike Pence, now Indiana’s governor — reported Souder to House Ethics and looped in then-Minority Leader John A. Boehner. The Ohio Republican then wrote the panel to support an investigation, and convinced Souder it was in his interest (and that of “the team”) to resign right away.

Just two months before, the same message had been delivered to freshman Rep. Eric Massa, a Democrat from upstate New York. Giving up on his re-election bid but serving out his term was not a viable option, his leadership declared soon after learning Ethics was investigating allegations of sexual harassment made by at least one male aide in Massa’s office. After he resigned, several other men on the staff described situations with Massa where they were groped, propositioned, spoken to obscenely and even forced into tickle fights.

Both sides appeared to be acting so forcefully in part because of what had happened four years earlier, when Democrats seized control of the House by campaigning against the GOP for fostering a “culture of corruption” while in charge. A main exhibit in their case was that of Mark Foley, a veteran Republican who had been preying for years on teenage boys who served as House pages. Foley resigned five weeks before the 2006 election, as soon as a cache of his sexually explicit text messages to the pages became public.

Once a member leaves, House Ethics has no standing to investigate his or her behavior while in office. Instead, the panel launched an investigation concluding that GOP leaders and House officers had remained intentionally asleep at the switch when they could have confronted mounting evidence of Foley’s inappropriate behavior.

Two years later, there was no need for an ethical inquiry into the behavior of Democratic Rep. Tim Mahoney, who happened to be Foley’s congressional successor in south-central Florida. A month before the 2008 election, it was revealed that the married Mahoney had secretly agreed to pay $121,000 to a former mistress, district caseworker Patricia Allen. He also arranged a job for her at a local advertising agency in return for her dropping a lawsuit claiming sexual harassment and intimidation. (She said she was fired from her House job after she broke off their relationship.)

Mahoney lost his re-election bid by 20 points.

The only suspense in the McAllister matter is which lesson the newcomer congressman is going to apply from the stories of these notorious predecessors.

Correction: 7:06 p.m.

An earlier version of this post misidentified Massa’s party.