Republicans have been whining for years that Clinton was not really punished for his blow job, but they get in trouble every time they furtively park outside the Senate page dorm in the middle of the night and do god knows what until the Capitol Police show up.
But the pendulum seems to have swung the other way lately, with John Edwards, Eliot Spitzer, and Eric Massa all having been "driven from public life." Meanwhile, John Ensign, David Vitter, Mark Sanford, and Jim Gibbons all still have their jobs!
Then consider the folks on the other side of the aisle. Ensign's sex scandal, which appears to include possible criminal misconduct, hasn't interfered with him remaining a Republican senator in good standing. Sen. David Vitter (R-La.), another right-wing, "family-values" hypocrite, got caught with a prostitute. Not only did he stay in office, but he's seeking re-election — and polls show him winning. Gov. Mark Sanford's (R-S.C.) sex scandal got plenty of coverage, but note that he's still the governor. Nevada Gov. Jim Gibbons (R) found himself in a sex scandal, but like Vitter, he not only stayed in his job, but he's running for another term, too. Former Sen. Larry Craig (R-Idaho) was caught up in an especially humiliating controversy, but he didn't resign before the end of his term, either.
Ok, guys, you're both really smart bloggers, so it's weird that you didn't notice what those shamed Republicans all have in common: they just didn't resign. And eventually the media moved on to the next thing.
The governor of New York doesn't really have the luxury of waiting out the press, but the fact remain that Spitzer just up and quit. Here is a good counterexample for your list, Steve Benen: the current governor of New York, who admitted to sex and drugs and all that, and who is also, Larry Craig-style, planning to finish his term.
But Ensign and Vitter just... refused to resign. When we say Massa and Spitzer were "forced out," we mean they bowed to pressure and decided, themselves, to quit. Edwards has nothing to resign from, so I really don't know what he has to do with anything. (Is the press coverage outsized? He ran two credible presidential campaigns and ended up on a major party ticket!)
So, yes, it is hilarious that John Ensign and David Vitter and Mark Sanford haven't resigned, but that is because of their shamelessness, not anyone's double standard. (That said, everyone should totally be talking more about the John Ensign revelations, and we should all be careful to note, as often as possible, that Senator David Vitter has sex with hookers while wearing diapers.)