In 2008, as the nation faced a catastrophic financial crisis, the House did what it sometimes does — veered off the rails. In a raucous and startling floor vote, lawmakers defeated a $700 billion bank bailout, sending the markets plummeting as the economy teetered. It was the steadier Senate that had to step in and take over, find a way to approve the legislation and show the House how it was done.

That has often been the way in Washington. When the unruly House, with its treacherous two-year election cycle, melts down, the Senate is expected to step up, providing the adult supervision needed in the legislative world. But developments over the past week show that those days may be coming to a close. The august Senate — at least on the Republican side — is becoming more like its chaotic counterpart across the Rotunda every day.

The Senate Republican Conference, as it is known, is more publicly divided and feuding than at any time in recent memory, a rare development for a group led by Senator Mitch McConnell, Republican of Kentucky and the minority leader, who has always taken great pains to conceal internal disputes. Mr. McConnell himself is now taking withering fire from the far right of the rank and file as conservatives offer a scathing critique of his stewardship.

These days, Republican senators say their weekly luncheons often deteriorate into angry gripe sessions. They have broken into warring factions, the same dynamic that has tied up the House majority.