The Congressional Black Caucus has called on House Speaker John Boehner to strip Republican Rep. Darrell Issa of his chairmanship of a key House committee after Issa’s treatment of Rep. Elijah Cummings (D-Md.) at a Wednesday hearing. But Boehner said he is standing by Issa.

Issa scheduled a hearing of the Oversight and Government Reform Committee to get testimony from former IRS official Lois Lerner on the IRS “scandal” that the Republicans have been pushing for the past year, but that has been widely and thoroughly discredited. Republicans claim the IRS singled out conservative groups for special scrutiny, when IRS officials have repeatedly said they investigated all political groups seeking nonprofit status.

At Wednesday’s hearing, after Lerner invoked the Fifth Amendment and refused to speak — as Issa had been told she would — Issa adjourned the meeting and cut off Cummings’ microphone, gesturing with his hand across his neck.

“Mr. Issa is a disgrace and should not be allowed to continue in a leadership role,” Rep. Marcia Fudge (D-Ohio), head of the Congressional Black Caucus, wrote in the strongly worded letter to Boehner.

But Boehner had no interest in such a move, saying the California congressman was not out of line to cut off Cummings’ microphone and walk out.

“He was within his rights to do what he did,” Boehner said, later adding: “Darrell Issa is the chairman, he’s done an effective job as chairman and I support him.”

Salon columnist Joan Walsh invoked the ire of conservatives when she called Issa’s behavior “thuggish.”

Walsh revealed that Lerner’s attorney had offered last month to share her answers to the committee’s questions via what’s called a “proffer,” which is when the subject of an investigation reveals the rough outlines of what they know. The purpose is usually to determine whether they deserve immunity from prosecution. But Issa rejected the proffer, deciding instead to stage a spectacle with the purpose of trying to embarrass the White House.

“Issa showed remarkable contempt for Cummings on Wednesday, but he also showed contempt for the American people,” Walsh wrote. “Issa’s investigation has cost at least $14 million, and eaten up 97,542 hours of IRS staffers’ time. The agency has coughed up more than 500,000 pages of documents; 35 former and current IRS employees have sat for interviews. Treasury and IRS officials have testified at 15 separate congressional hearings. After all of that, a leader who wanted the truth would have listened to what Lerner had to say through her attorney. That’s not what Issa’s after. He’s trying to shame the White House, and Cummings makes a great stand-in.”

Issa told a San Diego-based publication that he had called and apologized to Cummings.

“Mr. Cummings is a member of Congress who works very hard for his constituents,” he said.

Cummings had told reporters that he “didn’t want to get caught up in the disrespect,” but said Issa had been “undemocratic and unfair.”

“A number of Republican members on our committee have come up and said to me, ‘Don’t tell him, but I apologize. You shouldn’t have been treated that way,’” Cummings said.

House Minority Leader Nancy Pelosi (D-Calif.) told reporters at her weekly press briefing that Issa’s behavior toward Cummings was disrespectful.

“I can’t see how Republicans wouldn’t be running…to disassociate themselves from such behavior,” she said. “You would think they would be heading to the hills.”