There are too many loose cannons rolling around in Congress these days, and now one of the loudest, Rep. Darrell Issa of California, may have fired once too often.

Issa, chairman of the House Committee on Oversight and Government Reform, is taking a beating from Democrats and not getting much support from his fellow Republicans in the wake of an ugly confrontation with the committee’s ranking Democrat, Rep. Elijah Cummings of Maryland, on Wednesday.

Issa abruptly adjourned a committee hearing and turned off Cummings’ microphone as the Marylander tried to complain about the chairman’s treatment of other Democrats and his handling of a committee investigation of allegations that the Internal Revenue Service has harassed Tea Party groups.

“Shut it down,” Issa said, flicking a finger across his neck to signal staffers to cut the sound system.

Irate, Cummings kept talking. “Mr. Chairman, You cannot run a committee like this,” he declared.

Once upon a time — actually not so long ago — this sort of exchange would have been unthinkable in the House. Members might make secret deals and stab one another in the back — figuratively of course — but it was all done behind the scenes. In front of the cameras and the microphones, they smiled and addressed one another as “the distinguished gentleman” or “the distinguished gentlewoman.”

Those days are gone, pushed out the door by headline- and airtime-hunting members in both parties. But the high-handedness of Issa’s treatment of Cummings was out-of-bounds even by today’s standards.

Members of the Congressional Black Caucus led a parade of Democrats onto the House floor on Thursday to introduce a resolution calling on Speaker John Boehner to rebuke Issa and withdraw his chairmanship. No one expects Boehner to do that, but the Speaker gave Issa a somewhat less-than-ringing vote of confidence. And while Democrats were rallying around Cummings, Issa’s fellow Republicans weren’t rushing to the microphones to defend the chairman.

It’ll be interesting to see what happens next. Will Issa offer an apology or make a conciliatory gesture? If he does, will the Democrats withdraw their resolution? Unless someone — or both — steps back, the dysfunction that already characterizes the House is about to get worse.