WASHINGTON — Senate Democrats struck a deal last week with Republicans that saw the quick confirmation of 15 more conservative judges in exchange for a rapid flight to the campaign trail. Liberal activists were infuriated, but after the brutally divisive fight to confirm Justice Brett M. Kavanaugh, the agreement held out a promise of peace.

“I would like to have the future mending things,” declared the chairman of the Senate Judiciary Committee, Senator Charles E. Grassley, Republican of Iowa.

On Wednesday, at Mr. Grassley’s instruction, the armistice collapsed.

Republicans on the Judiciary Committee convened yet another hearing to consider still more conservative federal court nominees — while the Senate was technically in recess. Incensed Democrats boycotted the proceedings, but their empty chairs did not prevent candidates for the bench, such as Allison Rushing, 36, a social conservative nominated by President Trump to the United States Court of Appeals for the Fourth Circuit, from taking a crucial step toward confirmation.

“If there was ever any hope that after the Kavanaugh experience we could return to bipartisanship on the Senate Judiciary Committee, it was shaken this morning,” said Senator Richard J. Durbin of Illinois, the No. 2 Democrat in the chamber, in a telephone interview.

The hearing demonstrated the lengths to which Republicans will go to put conservatives on the federal judiciary, a signature initiative of Mr. Trump and Senator Mitch McConnell, Republican of Kentucky and the majority leader. Only a handful of Republicans attended the Wednesday hearing, but it checked a box to move more judges to the floor during the lame-duck session after Election Day.

Ms. Rushing is drawing protests from liberal advocacy groups who say her résumé is too thin for an appeals court nominee. She clerked for Justice Clarence Thomas and Judge Neil M. Gorsuch, before he became a Supreme Court justice, but is only 11 years out of law school and has never been a judge. If confirmed, she would become the youngest nominee to take the federal bench in more than 15 years.

Even Senator John Kennedy, Republican of Louisiana, pressed Ms. Rushing about her youth and inexperience.

For their part, Democrats are facing some serious blowback from progressives, who were already up in arms over last week’s deal. Brian E. Fallon, the executive director of Demand Justice, a liberal advocacy group, said Democrats should have demanded that Wednesday’s hearing, and another one scheduled for next week, be delayed as part of the recess deal.

“To me, it’s a sign that they didn’t just get stuffed in a locker here; they had their lunch money taken,” Mr. Fallon said.

He even took a public swipe at his former employer, Senator Chuck Schumer of New York, the Democratic leader.

The man who took Mr. Fallon’s place as Mr. Schumer’s spokesman, Matt House, said that criticism was unfair. Mr. House did not dispute that Republicans were violating the spirit of the peace offering, but he added that Democrats could do little beyond pushing judicial confirmations past the election. That has not changed.

“The agreement we reached will prevent any additional judges coming out of the Judiciary Committee from being confirmed before the election,” Mr. House said. “Had we not adjourned until after the election, Senate Republicans would have been able to not only hold this hearing, but get additional judges on the bench before Election Day.”

In the minority, Democrats have no power to determine when hearings are held. And should they remain in the minority next year, they will still have little recourse as Mr. McConnell and Mr. Trump move to fill the courts with conservatives.

With Mr. Grassley absent, Mr. Kennedy acted as the chairman for Wednesday’s hearing. Three other Republicans — Senators Orrin G. Hatch of Utah, Ben Sasse of Nebraska and Michael D. Crapo of Idaho — made brief appearances, throwing mostly softball questions.

“I’m very proud of you,” Mr. Hatch told Ms. Rushing. Mr. Sasse called her an “inspired choice.”

Mr. Kennedy, though, tried to draw her out with a string of offbeat questions: “Tell me about your major disappointment in life.” (She said she spent too much time focusing on work and not enough on family, as her husband held their 11-month-old daughter behind her.) “Have you ever failed at something?” (Sports, she said.) “What’s the worst mistake you ever made practicing law?” (She said her associates usually caught her mistakes.)

Finally, sounding frustrated, Mr. Kennedy asked about colleagues Ms. Rushing admired at the law firm of Williams & Connolly, where she is a partner. “Why shouldn’t we appoint them? They’ve been at it awhile. They’ve had a little life experience; they’ve had disappointments, had to pick themselves back up on their feet and keep going,” he said, adding, “I think to be a really good federal judge, you’ve got to have some life experience.”

He said after the hearing that he had not yet decided how he would vote.

Ms. Rushing’s conservative credentials are well established. She is a member of the Federalist Society, the conservative legal group that has been advising the Trump administration on judicial nominees. She has also worked for the Alliance Defending Freedom, a Christian nonprofit whose clients include Jack Phillips, the Colorado baker whose refusal to make a wedding cake for a gay couple led to a Supreme Court case.

Five district court nominees — Thomas P. Barber, Wendy Williams Berger, Rodney Smith and T. Kent Wetherell II, all state judges in Florida, and Corey Landon Maze, a special deputy attorney general for Alabama — also came before the committee on Wednesday, facing questions about issues including the First Amendment and racial preferences in college admissions.

But Mr. Kennedy seemed to stump one of them, Judge Barber, when he asked whether Federal District Court judges possess the authority to issue “nationwide injunctions” barring the federal government from enforcing a law against anyone, not just against the plaintiffs before them.

“What’s the legal basis for that?” Mr. Kennedy asked.

“Senator, I will confess, I’ll say this much: I don’t know a lot about that,” Judge Barber replied. “I took several courses in law school in federal courts. I never learned about that. It was never taught. So it seems rather new.”

Mr. Grassley has said the top Democrat on the Judiciary Committee, Senator Dianne Feinstein of California, agreed to Wednesday’s hearing and another to follow it.

But a spokeswoman for Ms. Feinstein — who is seeking re-election and was scheduled to appear on Wednesday night at a debate in California — said she agreed only because she thought the Senate would be in session.

“This is a travesty,” said Nan Aron, the founder and president of the Alliance for Justice, a liberal advocacy group. “It’s a stealth effort to confirm a nominee who might not withstand the scrutiny of the full committee.”

Both Mr. Kennedy and Mr. Crapo said Wednesday that Republicans were justified in moving ahead, arguing that Democrats had been stalling Mr. Trump’s nominees. The numbers, though, suggest otherwise: Senate Republicans have so far used their narrow majority to confirm 29 appeals court judges nominated by Mr. Trump, far more than any other president since the creation of the regional circuit court system in 1891. They have confirmed an additional 53 district court judges.

Mr. Kennedy acknowledged “hard feelings” after the Kavanaugh fight, and said that perhaps the judiciary panel should go out to dinner as a group to talk things out.

As to whether he was further damaging comity by leading the session, the senator shrugged: “This bed was on fire when I laid down in it.”