Senate Majority Leader Harry Reid has high standards for American-ness.

That’s why it carried such weight when he described the Koch brothers in a speech on the Senate floor as “about as un-American as anyone that I can imagine.” Coming from anyone lacking Reid’s powers of patriotic discernment, this would have been shameful hyperbole. From Reid, it was a peerless act of taxonomy.

What immediately had him so exercised was anti-Obamacare ads funded by the Koch brothers, but surely other potentially un-American activities lurked in the back of his mind. David Koch gave $100 million to a theater in New York City so people can perform ballet and opera there. No wonder Reid harbors the darkest suspicions.

If you want to score a contest between the Koch brothers and Harry Reid over who has contributed more to America, it doesn’t seem close. The Koch brothers got wealthy creating productive industries that employ tens of thousands of people. Harry Reid got (obviously much less) wealthy as a career politician.

Any one of the Koch brothers’ many major philanthropic ventures — say, the $100 million to New York Presbyterian Hospital, or just the $35 million to the Smithsonian’s National Museum of Natural History — will do more good than Harry Reid’s constant maneuvers to try to protect his vulnerable incumbents.

Reid’s maligning of the Koch brothers is part of a partywide effort to attack the politically engaged libertarian duo. Groups that the Kochs have donated to or are affiliated with have spent some $30 million on the midterm elections so far, with more on the way. For Democrats, that is a mortal sin.

Of course, Reid didn’t complain about a globe-trotting billionaire who made a mint through currency speculation spending more than $25 million trying to defeat President George W. Bush in 2004. By Reid’s standard, George Soros was as robustly American as John Wayne.

The left doesn’t lack for people trying, in Reid’s stilted terms, “to buy America.” Green billionaire Tom Steyer has pledged to spend $100 million supporting Democrats this year. The billionaire Koch brothers can agitate against cap and trade, and billionaire Steyer can agitate for it. That’s how a free system works.

But the break-glass-in-emergency Democratic option in tough midterms is finding a boogeyman. In 2010, it was “secret foreign money” funneled through the Chamber of Commerce. This absurdly tendentious demagoguery didn’t stop Republicans from picking up more than 60 House seats.

Nor will the attack on the Kochs affect this year’s outcome one way or another. Are we supposed to believe that voters, who are overwhelmingly sour on Obamacare, will ignore their feelings about the highly consequential law and treat the midterms as a referendum on the people funding ads attacking the law that they don’t like in the first place?

The left can be forgiven for thinking everyone else is as obsessed with the Koch brothers as it is. The log on the Koch Industries website of New York Times stories mentioning the Kochs since 2011 runs about 20 pages when printed.

The logical endpoint of this anti-Kochery was the spectacle of left-wingers protesting the coming advent of the David H. Koch Center at New York Presbyterian Hospital because of its association with a philanthropist with uncongenial politics. How long before demonstrators target the David H. Koch Theater at Lincoln Center and interrupt “Swan Lake” with cries of “Koch Kills Democracy”?

The old Saul Alinsky dictum is apt: “Pick the target, freeze it, personalize it, and polarize it.” In its piece on Reid’s anti-Koch gambit, The New York Times reports, “The majority leader was particularly struck by a presentation during a recent Senate Democratic retreat, which emphasized that one of the best ways to draw an effective contrast is to pick a villain.”

How high-minded. For a powerful national officeholder to stoop to such invective against private citizens seems bullying and itself vaguely un-American. But I defer to Harry Reid. He is the expert on American-ness.