Thank goodness for Sen. Harry Reid (D-Nev.) What would Republicans do without him?

President Obama and his cheerleading squad in the media had been flogging the tax-return issue — Mitt Romney’s, not yours — for weeks. Sure, the attack had worn thin, but like Bain it was poised, you knew, to make a comeback. Enter, Harry.

The Las Vegas Review Journal reports:

Sen. Harry Reid caused a stir this week when he told an interviewer that Mitt Romney hasn’t released more of his tax returns because “he didn’t pay taxes for 10 years.” On Wednesday, Reid doubled down on the charge.

In an interview published Tuesday, Reid said an investor in Bain Capital, the former private equity firm of the Republican presidential candidate, told him in a phone call that Romney had paid zero taxes.

“Now, do I know that that’s true? Well, I’m not certain,” Reid told the Huffington Post, declining to identify his source. “But obviously he can’t release those tax returns. How would it look?”

His poor father must be so embarrassed about his son,” Reid said, referring to then-Michigan Gov. George Romney making public 12 years of his tax returns when he ran for president in 1968.

The Twitter razzing and blog criticism descended on Reid for his baseless, scurrilous charge, one that never made much sense. (How would an investor have seen Romney’s tax returns?). His tasteless reference to Romney’s deceased father raised memories of Hillary Clinton’s communing with Eleanor Roosevelt. In short, Reid made himself look like a malicious, foolish hatchet man. His sin was not character assassination (the entire left has been doing nothing but); rather, it was clumsiness in its practice. You could hear Democrats grinding their teeth.

Jon Stewart got into the act, skewering Reid. And just like that the Democrats’ attack went up in a puff of smoke, the smoke Reid was blowing.

But really, Reid’s crime was only in being too blunt, too obvious in his nasty accusations. Democrats had been doing precisely the same thing, digging up “experts” to tell us Romney “probably” paid no taxes and making the analogy to George Romney. (Note to file: When an “expert” in medicine , taxes or anything else renders opinions without access to any relevant facts he’s not an “expert.”) They got away with it because they were more sophisticated purveyors of the same slurs. Now — too bad for them — the gambit is up.

Romney, you say, brought this one on himself. Only two years of tax returns?! Sheesh, he’s got some nerve. (No one much cared when Sen. John McCain (R-Ariz.) released exactly the same number.) Whatever the initial wisdom of his decision in the primary to release only two years’ of returns (why not do three or four?) he was dead right to stick to his position in the wake of the Bain Media Swarm and Oppo Fest. Now the Democrats have self-destructed on an issue on which, I am certain, not a single vote will be won on lost. Call it political karma.