Judge Barrett has been described as a protégée and intellectual successor to Justice Scalia, for whom she clerked. Educated at Notre Dame Law School, she served on its faculty for years before Mr. Trump appointed her in 2017 to the United States Circuit Court of Appeals for the Seventh Circuit.
During her confirmation hearings to that post, Democrats questioned her public statements and Catholicism, making her a hero to religious conservatives who denounced what they called unfair attacks on her faith. But liberals pointed to her writings to say they feared she would undo Roe v. Wade and other rulings on gay rights, health care and other issues.
“If she is nominated and confirmed, Coney Barrett would work to dismantle all that Ruth Bader Ginsburg fought for during her extraordinary career,” Alphonso David, the president of the Human Rights Campaign, which promotes rights for L.G.B.T.Q. Americans, said before Mr. Trump’s announcement. “An appointment of this magnitude must be made by the president inaugurated in January.”
Jeanne Mancini, the president of March for Life, an anti-abortion group, called Judge Barrett’s reported selection “exciting news” for conservatives. “We have confidence that she will fairly apply the law and constitution as written, which includes protecting the most vulnerable in our nation: our unborn children,” she said.
Polls show that most Americans say that the winner of the Nov. 3 election should fill the seat rather than Mr. Trump rushing through an appointment before then. But the president made clear this past week that he wanted his pick on the court in time to rule on any challenges arising from the election itself, guaranteeing what he hopes would be an additional vote to potentially secure a second term.
To confirm her by then would require a 38-day sprint through a process that since 1975 has typically taken twice as long, all at the same time many senators want to be in their home states to campaign. No seriously contested Supreme Court nomination has been confirmed so quickly since 1949.
Senator Lindsey Graham of South Carolina, the chairman of the Senate Judiciary Committee that will vet Judge Barrett’s nomination and himself an incumbent facing a serious election challenge, planned to outline the confirmation process for the first time in a statement Saturday night after the president’s announcement.