Senate Majority Leader Mitch McConnell (R-Ky.) meets with Supreme Court nominee Brett M. Kavanaugh last month. (Chip Somodevilla/Pool/Epa-Efe/Rex/Shutterstock/Chip Somodevilla/Pool/Epa-Efe/Rex/Shutterstock)

As the Senate moves toward confirming Supreme Court nominee Brett M. Kavanaugh, President Trump and Senate Majority Leader Mitch McConnell are leading a lower-key yet deeply consequential charge to remake the entire federal judiciary.

The Senate will return Wednesday from an abbreviated summer recess to confirm two more federal appeals court judges by the end of the week. That would come on top of a record-breaking string of confirmations: The Senate already has installed 24 appellate judges since Trump was sworn in, the highest number for a president’s first two years in office.

While much of the focus has been on Kavanaugh and Justice Neil M. Gorsuch, the Senate’s rapid approval of appellate judges is likely to have its own broad impact on the nation, as the 13 circuit courts will shape decisions on immigration, voting rights, abortion and the environment for generations.

For McConnell, this is the culmination of a years-long gambit that started with stymieing President Barack Obama’s judicial nominees, most notably Supreme Court choice Merrick Garland, and creating a backlog of vacancies on the nation’s highest courts.

Trump’s 2016 election enabled McConnell (R-Ky.) to cement a legacy of judicial confirmations that is likely to be felt long after the two men leave office. The Republican leaders are also trying to use judicial nominations to energize conservative voters, who party leaders worry will sit out the midterm elections.

There are 179 authorized judgeships for the U.S. Court of Appeals. With 24 confirmations and 13 vacancies to fill, Trump and the Republicans have the power to install more than 20 percent of the judges on the nation’s second-highest courts.

“One of the most significant accomplishments in President Donald Trump’s first year will serve Americans for decades to come, yet it has received very little fanfare,” wrote McConnell with Senate Judiciary Committee Chairman Charles E. Grassley (R-Iowa) in a January National Review op-ed.

On Wednesday, the Senate plans to advance the nominations of A. Marvin Quattlebaum Jr. and Julius Ness Richardson, both for the U.S. Court of Appeals for the 4th Circuit. Both Quattlebaum and Richardson have bipartisan support, winning the votes of some Democrats when they were considered by the Senate Judiciary Committee.

“The Supreme Court gets the bulk of the attention, but the circuit courts decide the bulk of the cases,” said Arthur D. Hellman, a University of Pittsburgh law professor who studies the federal judiciary. “Because the Supreme Court these days is taking so few cases, the law of the circuit is, on many, many issues, the final law for the people who live in that circuit.”

Sen. Richard Blumenthal (D-Conn.), a member of the Judiciary Committee, said two of his children are beginning law school and that “these judges will be there for a good part of their legal careers.” The appeals court is “the backbone of the federal judiciary,” said Blumenthal, who said he regretted the “very unfortunate,” enduring legacy of Trump’s choices.

Virtually all of Trump’s nominees have graduated from top law schools, held Supreme Court clerkships or worked in big-name law firms or the Justice Department. But they also have affiliations with the Federalist Society or other conservative credentials. That, as well as past writings and cases, have sparked often fierce opposition from Democrats and liberal groups.

“These are not mainstream jurists being nominated because they are legal luminaries, but people who are coming to the bench with clear ideological-driven missions of eroding constitutional rights and legal protections,” said Daniel Goldberg, legal director for the Alliance for Justice, a liberal group focused on judicial issues.

Hellman said that Trump’s nominees have, so far, largely replaced retiring Republican-
appointed judges, and thus he has yet to wholly remake any of the 13 circuit courts. But he said at least one circuit — the 5th Circuit, covering Louisiana, Mississippi and Texas — is at a tipping point.

Last month, that court decided on an 8-7 vote not to reconsider a decision striking down a trial judge’s ruling that the federal law against selling firearms across state lines is unconstitutional. All four Trump appointees on that court would have reconsidered the case, opening the door to overturning a longstanding federal gun law. Since then, another Trump nominee has been confirmed to that court and there is another vacancy that Trump can seek to fill.

Democrats have sought to slow the confirmations, forcing every circuit court nominee to clear procedural hurdles. But a Democratic rule change in 2013 allowed most federal court nominees to advance to confirmation by a simple majority. McConnellchanged the Senate rules in 2017, to apply the same standard to Supreme Court nominees.

Under Trump, the pace of confirmations to the district courts, which are lower on the court hierarchy, has lagged behind Obama and George W. Bush.

“Twenty-four is excellent for two years,” said Ed Whelan, president of the conservative Ethics and Public Policy Center and a former law clerk to the late Justice Antonin Scalia. “But it needs to be sustained in order to have any real transformative effect.”

During the final two years of the Obama administration, in which Republicans controlled the Senate, the confirmation of judicial nominees slowed to a crawl — giving McConnell and Trump plenty of vacancies to fill starting in 2017.

Hours after Scalia’s death in February 2016, McConnell said the Senate would not consider any Obama nominee until the voters had their say in the presidential election. Democrats were enraged but powerless.

The decision paid huge dividends when Trump won in 2016 and nominated Gorsuch, a conservative choice widely hailed by Republicans. Gorsuch won the votes of all Republican senators and three Democrats.

Now, McConnell is confidently eyeing a confirmation vote for Kavanaugh this fall. The judge plans to meet Wednesday with Democratic Sens. Heidi Heitkamp (N.D.) and Joe Donnelly (Ind.). The two backed Gorsuch, face challenging reelection bids in states Trump won, and are feeling pressure to vote for Kavanaugh.

Russell Wheeler, a Brookings Institution visiting fellow who closely tracks judicial nominations, said that now more than ever, the confirmation process is more about hardball politics and less about cooperation between the parties. “It’s just dog-eat-dog for the moment, and we’ll worry about what happens when the tables get turned later,” he said. “I don’t see how you ratchet it back.”

The Democratic attempts to defeat Kavanaugh have fallen flat, leading to finger-pointing within the party. Liberal activists have portrayed him as a threat to tilt the court toward erasing health-care protections and abortion rights — arguments that have shown virtually no signs of swaying most critical swing votes in the Senate.

McConnell is trying to use the Supreme Court pick, as well as the Senate’s work on lower court nominees, to spur conservative voters to participate in November’s midterms. Republicans are defending a 51-49 majority, and party leaders are bracing for a difficult election, due to Trump’s unpopularity.

A Pew Research Center poll in July found conservative Republicans more likely than moderate and liberal Republicans to say the choice of the next Supreme Court justice was very important to them.

Steven Law, a former McConnell aide who is now the president of the conservative group American Crossroads, predicted that the Supreme Court and judicial nominations more broadly “will be part of our pitch to conservatives on why their vote matters this fall.”

Exit polls conducted in the 2016 election found that 7 in 10 said Supreme Court appointments were the most or an important factor in their vote. Among Trump voters, 26 percent said it was “the most important factor,” and 48 percent said it was “an important factor.”

“It was a way for him to reassure people who didn’t really want to vote for Hillary Clinton that he was going to be, even though he was quite unusual, he was going to be a real Republican,” McConnell said of Trump in an interview with The Washington Post this summer.

McConnell, who titled his memoir “The Long Game,” frequently reminds his allies that the Senate is in the personnel business. He’s had a rocky relationship with Trump since his election, but the confirmed judges have given them a common goal.

Republicans face difficult political head winds in November, with some on the right fearful they will soon lose their plum chances to push through court nominees.

“If the Republicans lose the Senate in November, the great start will be nothing more than a great start,” said Whelan.

Emily Guskin, Seung Min Kim and Paul Kane contributed to this report.