WASHINGTON — Stung by a fierce backlash from Donald J. Trump’s ardent supporters, four Republican members of Congress who had made headlines for demanding that Mr. Trump leave the presidential race retreated quietly this week, conceding that they would still probably vote for the man they had excoriated just days before.

From Senator John Thune of South Dakota, the only member of the Republican leadership in either chamber who had disavowed Mr. Trump, to Representative Scott Garrett of New Jersey, who is in a difficult re-election fight, the lawmakers contorted themselves over Mr. Trump. Some of them would not mention him by name, preferring instead to affirm their support for the generic “Republican ticket,” still grasping for a middle ground.

They said that if Mr. Trump would not make way for his running mate, Gov. Mike Pence of Indiana, to lead the party after the release of a recording on Friday showing Mr. Trump bragging about groping women, they had little choice but to vote for their embattled nominee. But the collective about-face owed less to his refusal to exit a race in which ballots are already being cast than to the fury his supporters unleashed at the defectors at rallies and on social media.

And Mr. Trump himself escalated his bitter feud with the country’s highest-ranking elected Republican, Speaker Paul D. Ryan, saying at a rally in Florida on Wednesday that Mr. Ryan’s refusal to actively support his candidacy was part of a “sinister deal going on.”