Rich Lowry is not sitting by idly as the U.S. Senate majority leader impugns the political activity of two wealthy libertarian brothers from the Midwest. Lowry shares his assessment on the issue for Politico readers.

Senate Majority Leader Harry Reid has high standards for American-ness. That’s why it carried such weight when Reid described the Koch brothers in a speech on the Senate floor as “about as un-American as anyone that I can imagine.” Coming from a typical Democratic politician 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. Has David Koch never thought to invest in cowboy poetry? No wonder Reid harbors the darkest suspicions about his true loyalties.

Actually, of course, Harry Reid long ago established his comfort making any half-witted partisan attack. In his cracked version of forensic accounting, he said in 2012 that Mitt Romney hadn’t paid taxes in 10 years — because he had heard it from some guy.

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 deliberate, party-wide 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.