WASHINGTON — Senators, looking toward November’s elections after a bruising Supreme Court fight, reached an agreement on Thursday to leave the Capitol for the campaign trail.Republicans exacted a steep price from Democrats for an arrangement that will free up senators through Election Day: In a flurry of votes late Thursday, they pushed through 15 more judicial nominees, including three appeals court judges, on an expedited basis. In doing so, they added an exclamation mark to their victory in muscling through a second Trump Supreme Court justice, and deepened a historic imprint on the federal judiciary in President Trump’s first two years in office that could push some of the nation’s most important courts rightward for a generation.Democrats agreed to swallow the additional nominations to free up their vulnerable members to campaign full time for the next three weeks. The party is defending seats in 10 states that Mr. Trump won in 2016, and after a polarizing confirmation fight over Justice Brett M. Kavanaugh, many of those senators are facing greater enthusiasm among Republican voters. Republicans, by comparison, are defending a much smaller number of vulnerable seats, and they had elected to keep the Senate in session later than is typical in an election year.At least one endangered Democrat, Senator Heidi Heitkamp of North Dakota, was already back in her home state campaigning as senators pushed through the nominees.But the agreement enraged liberal groups who have tried to galvanize opposition to Mr. Trump’s nominees. Chris Kang, the chief counsel for one such group, Demand Justice, accused Democrats of “weakness” in allowing so many nominations to advance and called Thursday’s deal “totally unnecessary” and “a bitter pill to swallow so soon after the Kavanaugh fight.”Senate Democratic leaders defended the decision as an obvious one. They said that even if they had remained in Washington to slow the confirmation process, Republicans would still have been able to process all the judges by early November. With only a simple majority required to confirm judges, Democrats are unable to stop any nominee on their own.Still, the achievements for conservatives are striking. By Thursday night, Senate Republicans had used a 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 had added to the bench an additional 53 district court judges. And after last week’s near-party-line Supreme Court vote, they have secured a conservative majority on the court that could last for a generation.It took most of President Barack Obama’s first term for a Democratic Senate to confirm a similar number of appellate judges. Once the latest judges are seated, roughly one in every six appeals court judges in the country will be Trump appointees.After spinning through judicial victory laps all week, Senator Mitch McConnell of Kentucky, the majority leader, left the Senate floor without comment Thursday evening — a sign that even Republican leaders were eager to get out of town.If Democrats win control of the Senate next month, they could bring the rush of confirmations to an abrupt halt, much as Mr. McConnell did when Republicans won control of the Senate for the last two years of Mr. Obama’s presidency. But that prospect remains unlikely, and Mr. McConnell has more judicial nominees in waiting. (Mr. McConnell’s refusal to advance Mr. Obama’s nominees helped create the large number of vacancies Mr. Trump has been able to fill.)The House, where Republicans are in far greater danger of losing their majority, has long since decamped from Washington. House lawmakers have spent few days here since late July, and after finalizing a series of government funding bills in late September, Republican leaders freed their members stay home through Election Day.When they return in mid-November, both chambers must settle a longstanding dispute over funding that Mr. Trump wants for a wall along the southwestern border and other border security provisions. Democrats and some Republicans have adamantly refused to pay for a physical wall, which they say would be costly and ineffective. But the president’s allies are willing fight for it. And Mr. Trump has threatened to veto a bill funding the Homeland Security Department and other parts of the government without it.