• President Trump is set to announce his Supreme Court nominee to replace the retiring Justice Anthony M. Kennedy at 9 p.m. Monday.
• Mr. Trump is deciding among four finalists, all federal appellate judges: Amy Coney Barrett of the Seventh Circuit, Brett M. Kavanaugh of the District of Columbia Circuit, Raymond M. Kethledge of the Sixth Circuit and Thomas M. Hardiman of the Third Circuit. All four were on a list of 25 candidates the White House compiled with input from the conservative Federalist Society and Heritage Foundation.
• Mr. Trump considers the pick a key moment of his presidency, and was pushing his decision into the final hours before his self-imposed Monday night announcement deadline.
Trump expressed renewed interest in Hardiman as he continued weighing the finalists.
On Sunday, The New York Times reported that Mr. Trump had expressed renewed interest in nominating Judge Hardiman, who was the runner-up to Judge Neil M. Gorsuch as the president’s first Supreme Court nominee in January 2017.
Mr. Trump was inspired by Judge Hardiman’s biography, according to people close to the process, and has considered the recommendation of his sister, Judge Maryanne Trump Barry, who served with Judge Hardiman on the United States Court of Appeals for the Third Circuit.
Judge Hardiman was also, along with Judge Kethledge, one of two finalists Senator Mitch McConnell of Kentucky, the majority leader, recently recommended to Mr. Trump and the White House counsel, Donald F. McGahn II, arguing that they posed the least risk of a confirmation failure.
Mr. McConnell saw drawbacks in the others. Judge Kavanaugh once argued that President Bill Clinton could be impeached for lying to his staff and misleading the public, a broad definition of obstruction of justice that would be damaging to Mr. Trump if applied in the special counsel’s Russia investigation. And Judge Kavanaugh has been viewed with suspicion by conservatives wary of his connection to President George W. Bush, for whom he served as staff secretary.
Judge Barrett, a former law clerk for Justice Antonin Scalia, has been championed by conservative Christian leaders, but Mr. McConnell fears she could cause the defection of two key Republican moderates in the Senate. (During her confirmation hearings last September for an appeals court seat, she told senators that her religious beliefs would not affect her judicial decisions.)
Mr. Trump told reporters late Sunday afternoon that he was still considering all four finalists, and that he would make his decision by noon on Monday at the latest.
“Every one, you can’t go wrong,” he said.
Democrats want to put up a fight, but may not be able to.
Democrats made it clear over the weekend that the bar is high for their votes. But they acknowledged how hard it would be to stop a nominee who has unanimous support among Senate Republicans.
Senator Chris Coons, a Delaware Democrat on the Judiciary Committee, admitted on Sunday that Democratic opposition could be futile. Even if all 49 members of their caucus united in opposition, they would still need at least one Republican to join them to block the nomination.
“It will be very difficult,” Mr. Coons said on CBS’s “Face the Nation.” “If all the Republicans stick together, along with the vice president, they’ll be able to confirm whomever President Trump nominates.”
Senator Richard J. Durbin, the No. 2 Senate Democrat, said on Sunday that Mr. Trump’s nominee would most likely be in the mold of Justice Gorsuch, who received unanimous Republican support in his confirmation vote and who Mr. Durbin said had voted “in lock step on the Republican conservative side.”
“They want to fill this vacancy to give them an advantage in any future rulings,” Mr. Durbin said on NBC’s “Meet the Press.”
Senator Chuck Schumer, the Democratic leader, wrote in a Times Op-Ed last week that if Mr. Trump’s first candidate failed, it would be wise to select a more moderate nominee. In a phone call with Mr. Trump, Mr. Schumer even floated the idea of nominating Judge Merrick B. Garland, President Barack Obama’s failed nominee in 2016.
The nomination vote will be difficult for Senate Democrats in red states who are up for re-election in November, including Heidi Heitkamp of North Dakota, Joe Donnelly of Indiana and Joe Manchin III of West Virginia. A decision by one or all of them to try to bolster their standing with Republican-leaning voters would undermine Democratic leaders.
Democrats fear that Mr. Trump’s nominee could favor the reversal of Roe v. Wade, the Supreme Court’s 1973 decision that established a constitutional right to an abortion. Here is what each of the four finalists has had to say on the topic.
Will the nominee arrive in secret? Will the runner-up be a decoy?
Whereas Mr. Obama opted for conventional ceremony in announcing his Supreme Court nominees, Mr. Trump prefers prime-time spectacle. Last year’s nomination of Justice Gorsuch was framed as a reality television-like cliffhanger: Who would it be? Were both finalists backstage at the White House? Would Mr. Trump change his mind at the last minute?
Dozens of lawmakers, family members and aides gathered in the East Room of the White House, where Mr. Trump made a red carpet entrance, then delivered a two-minute-long preamble, prolonging the mystery. When he revealed his selection, Mr. Gorsuch and his wife entered the room to a standing ovation.
“So was that a surprise?” Mr. Trump asked the crowd with a grin. “Was it?”
Adding to the suspense, a camera crew had spotted Judge Hardiman driving in Pennsylvania just hours before Mr. Trump announced his choice. Judge Hardiman claimed he was merely visiting someone in Altoona, a Pennsylvania town about 100 miles east of Pittsburgh, where Judge Hardiman keeps his chambers. But White House aides suggested that it was part of a plan to distract the news media.
Mr. Trump seemed to rely on that kind of speculation to enhance the drama of the televised selection. Word of the pick leaked only selectively in the hours leading up to the event, meaning many of those tuning in were learning of Mr. Gorsuch’s nomination for the first time as Mr. Trump read out his name.
After Judge Gorsuch heard the good news from Mr. Trump, he and his wife traveled on a military jet from a Colorado airport to Joint Base Andrews. The day of the announcement, he was smuggled into the White House, where aides had him wait in the Lincoln Bedroom before his appearance with Mr. Trump.