House Republicans were in the minority for many decades, and those who remember that long period know what it was like to be regularly steamrollered by Democratic leaders. For the most part, they’ve agreed to a basic understanding in the House that members of the minority have a right to speak up in disagreement. They can be ignored, and they usually are, but if they’re muzzled, it makes the majority look like a bunch of insecure authoritarians. And it could come back to haunt them if the majority shifts again.

That’s why Darrell Issa’s actions on Wednesday were so shocking to House decorum. Mr. Issa, a California Republican who is chairman of the Oversight and Government Reform Committee, refused to let the panel’s ranking Democrat, Elijah Cummings of Maryland, ask any questions at a hearing about the Internal Revenue Service’s investigation of non-profit groups. Mr. Issa had been castigating a former I.R.S. official, Lois Lerner, for taking the Fifth Amendment, and when Mr. Cummings tried to take his normal turn to ask a question, Mr. Issa adjourned the meeting and cut off Mr. Cummings’ microphone.



This kind of behavior is typical of Mr. Issa, who runs his committee like a permanently angry Marine drill sergeant. Democrats held news conferences and complained on television and introduced a resolution of disapproval, which of course will go nowhere. But as Nancy Pelosi, the minority leader, pointed out, this was bigger than mere rudeness.

“It’s about not hearing what you don’t want to hear,” she said.

There was a good reason Mr. Issa cut off his colleague. For months he has been on a single-minded crusade to prove the Obama administration ordered the I.R.S. to target conservative and Republican groups that spent unlimited secret money on political activity in 2012. He has accused the I.R.S. of targeting Americans for their political beliefs, a very serious charge for which he has produced not the slightest piece of evidence, clearly hoping that if he says it often enough, and loud enough, the message will sink in.

But Mr. Cummings has very effectively prevented that message from becoming accepted wisdom. He and the committee’s Democratic staff have shown that the I.R.S. didn’t just scrutinize Tea Party groups, but also groups with names that included “progressive” and “occupy.” That’s because the agency wasn’t on a political witch hunt, but was instead trying to figure out whether thousands of “social welfare” groups were abusing their tax exemptions by engaging in politics, of whatever stripe.

That undermines Mr. Issa’s narrative of aggrievement. It shows that Mr. Issa’s endless hearings are nothing more than hyperbolic stagecraft. And it’s exactly the kind of thing that House minorities are supposed to point out when it happens. For Mr. Issa, the fear of again being exposed as a fraud was greater than his fear of being accused of trampling on minority rights. When politicians reach for the microphone switch, you know they’ve lost the argument.