WASHINGTON — President Donald Trump nominated Judge Amy Coney Barrett to the Supreme Court on Saturday, capping a dramatic reshaping of the federal judiciary that will resonate for a generation and that he hopes will provide a needed boost to his reelection effort.

Republican senators are already lining up for a swift confirmation of Barrett ahead of the Nov. 3 election, as they aim to lock in conservative gains in the federal judiciary before a potential transition of power. Trump, meanwhile, is hoping the nomination will serve to galvanize his supporters as he looks to fend off Democrat Joe Biden.

Trump hailed Barrett as “a woman of remarkable intellect and character,” saying he had studied her record closely before making the pick.

“I looked and I studied, and you are very eminently qualified,” he said as Barrett stood next to him in the Rose Garden.

An ideological heir to the late conservative Justice Antonin Scalia, Barrett would fill the seat vacated after the Sept. 18 death of liberal icon Ruth Bader Ginsburg, in what would be the sharpest ideological swing since Clarence Thomas replaced Justice Thurgood Marshall nearly three decades ago. She would be the sixth justice on the nine-member court to be appointed by a Republican president, and the third of Trump’s first term in office.

For Trump, whose 2016 victory hinged in large part on reluctant support from conservative and white evangelicals on the promise of filling Scalia’s seat with a conservative, the latest nomination in some ways brings his first term full circle. Even before Ginsburg’s death, Trump was running on having confirmed in excess of 200 federal judges, fulfilling a generational aim of conservative legal activists.

“This is my third such nomination after Justice Gorsuch and Justice Kavanaugh, and it is a very proud moment indeed,” Trump said.

Trump joked that the confirmation process ahead “should be easy” and “extremely noncontroversial,” though it is likely to be anything but. No court nominee has been considered so close to a presidential election before, with early voting already underway. He encouraged Democrats to take up her nomination swiftly and to “refrain from personal and partisan attacks.”

In 2016, Republicans blocked President Barack Obama’s nomination of Merrick Garland to the Supreme Court to fill the election-year vacancy, saying voters should have a say in the lifetime appointment. Senate Republicans say they will move ahead, arguing the circumstances are different now that the White House and Senate are controlled by the same party.

Senate Majority Leader Mitch McConnell said the Senate will vote “in the weeks ahead” on Barrett’s confirmation, adding that Trump “could not have made a better decision” in nominating the appellate court judge.

The announcement came before Ginsburg was buried beside her husband this week at Arlington National Cemetery. On Friday, she was the first woman to lie in state at the Capitol.

Barrett said she was “truly humbled” by the nomination, adding that she would be “mindful of who came before me.” She praised Ginsburg upon accepting the nomination, saying, “She has won the admiration of women across the country and indeed all across the world.”

Within hours of Ginsburg’s death, Trump made clear he would nominate a woman for the seat, and later volunteered he was considering five candidates. But Barrett was the early favorite, and the only one to meet with Trump.

Barrett has been a judge since 2017, when Trump nominated her to the Chicago-based 7th U.S. Circuit Court of Appeals. But as a longtime University of Notre Dame law professor, she had already established herself as a reliable conservative in the mold of Scalia, for whom she clerked in the late 1990s.

The staunch conservative had become known to Trump in large part after her bitter 2017 appeals court confirmation included allegations that Democrats were attacking her Catholic faith. The president also interviewed her in 2018 for the vacancy created by the retirement of Justice Anthony Kennedy, but Trump ultimately chose Brett Kavanaugh.

While Democrats appear powerless to stop Barrett’s confirmation in the GOP-controlled Senate, they are seeking to use the process to weaken Trump’s reelection chances.

Barrett’s nomination could become a reckoning over abortion, an issue that has divided many Americans bitterly for almost half a century. The idea of overturning or gutting Roe v. Wade, the landmark 1973 decision that legalized abortion, has animated activists in both parties for decades. Now, with the seemingly decisive shift in the court’s ideological makeup, Democrats hope their voters will turn out in droves because of their frustration with the Barrett pick.

Trump has also increasingly embraced the high court — which he will have had an outsize hand in reshaping — as an insurance policy in a close election.