Newt and Marianne Gingrich in on-the-surface happier times, when they were still married and he was House speaker. (Mark Wilson/AP)

In June, we tried to figure out why some politicians survive sex scandals and others are undone by them. Chris Lehane argued that novelty is a key factor: Whereas affairs are old hat (“the public almost assumes that politicians” have them), an underwear shot on Twitter was strange new stuff — and ultimately ruinious for Anthony Weiner. As we noted in November, it seems that adultery is the new divorce — the thing that used to be an automatic deal-breaker for a politician but now eminently survivable. Well, sometimes: Didn’t work that way for Herman Cain.

In unrelated news, our colleagues at The Fix have determined that Rick Perry is only the third worst flameout in presidential campaign history. Who else makes the top 10? Read on.

Related: Newt’s ex: He wanted open marriage

Gingrich gains in S.C.

She the People: Marital history not an issue?

Earlier: Political sex scandals: Who survives, who crashes and burns? 6/5/11

Herman Cain affair: Still a political dealbreaker?, 11/29/11