(See the full list below)
Just 39 percent of officeholders won reelection after coming under scrutiny for sexual harassment, affairs or prostitution, while the rest chose not to run, resigned or lost. With 2012 reelection rates at 82 percent for House members and 81 percent for senators (with retirements included), suffering a public personal scandal cuts an officeholder's reelection chances in half. In all, politicians hang onto their jobs for a median of two years following significant reports of a personal scandal.
Still worse for McAllister, the survival rate has plummeted since Bill Clinton's presidency. In 15 scandals since 2000, just three officeholders (or 20 percent) facing personal scandals have won reelection. Several resigned in short order, including Reps. Anthony Weiner (lewd twitter messages), David Wu (untoward sexual advances plus a tiger costume) and Chris Lee (sharing a topless photo with a Craigslist contact). Sen. David Vitter (phone number on "D.C. Madam's" list) and Rep. Scott DesJarlais (accused of pressuring mistress to get an abortion) are still serving; former congressman Steven LaTourette left office in 2013 (affair with a staffer).*
In the 1990s, five of eight scandal-ridden politicians won reelection, including Bill Clinton and some of his chief Republican antagonists. Congressional officeholders faced similar odds in the 1970s, and fared a bit worse in the 1980s, none lost their jobs as consistently as in the past decade and a half.
About equal numbers of Democrats and Republicans have been caught up in such scandals (17 Dem, 22 Rep including McAllister), but Democrats have been twice as likely to win their next reelection contest as Republicans, 53 to 29 percent. At least part of the disparity owes to recency, with 11 of 15 sexual or adulterous scandals since 2000 involving Republicans, not including McAllister.
It's unclear why personal scandals that were once shrugged off -- or technologically impossible -- are more consequential today. Americans almost universally agree that extramarital sex is wrong, according to Gallup polls, but that has changed little in recent years. Most Americans say scandals are evidence of greater scrutiny for politicians rather than weaker moral standards.
But voters' rejection isn't the only factor in the impact of scandals. Since 2000, only five of 15 politicians facing scandals competed for another term in office, often succumbing to intense public pressure to resign, even from fellow partisans. Mirroring that trend, the Associated Press reported Wednesday that Louisiana Republican Party Chairman Roger Villere is trying to persuade McAllister to resign.
Where does McAllister fit? His freshman status and tenuous jungle primary victory last year make him vulnerable to challenges this year. And his actions carry similarities to past scandals -- potential for adultery, romance with a staffer -- but are far less damning than some officeholders whose careers survived. In 1983, Rep. Gerry Studds (D-Ma.) admitted to having a sexual relationship with a 17-year old page and remained in office for over a decade. More akin to McAllister's scenario, former senator Chuck Robb (D-Va.) won reelection after admitting he received a hotel room massage from a former Miss America pageant winner.
But the path in recent years has been dominated by defeats, which means McAllister is unlikley to overcome the hostile environment for personal scandals.
*A reader noted Rep. Scott DesJarlais was not initially included in the table below. He has been added to the analysis, with percentages updated accordingly. An earlier version of this post incorrectly stated LaTourette was still in office.
Peyton M. Craighill contributed to this report.