WASHINGTON (Reuters) - President Donald Trump said he will announce his nominee to the U.S. Supreme Court on Tuesday as he looks to quickly put his stamp on the court by restoring its conservative majority, even as Democrats geared up for a Senate confirmation fight.

A general view of the U.S. Supreme Court building in Washington, U.S., November 15, 2016. REUTERS/Carlos Barria

Trump, set to fill the lingering vacancy on the nation’s highest court left by the death of conservative Justice Antonin Scalia in February 2016, said on Monday he will reveal his choice at the White House at 8 p.m. on Tuesday (0100 GMT on Wednesday), two days earlier than previously planned.

Three conservative U.S. appeals court judges appointed to the bench by Republican former President George W. Bush were among those under close consideration. They are: Neil Gorsuch, a judge on the Denver-based 10th U.S. Circuit Court of Appeals; Thomas Hardiman, who serves on the Philadelphia-based 3rd U.S. Circuit Court of Appeals; and William Pryor, a judge on the Atlanta-based 11th U.S. Circuit Court of Appeals.

Since Scalia’s death, the Supreme Court has been ideologically split with four conservatives and four liberals. Another conservative justice could be pivotal in cases involving abortion, gun, religious and transgender rights, the death penalty and other contentious matters.

Trump’s appointee to the lifetime post could face stiff opposition from Democrats in the Republican-led U.S. Senate, which must confirm nominees to the high court. Some liberal groups have urged Democrats to do everything possible to block Trump’s nominee.

Democrats remain furious over Majority Leader Mitch McConnell’s refusal last year to allow the Senate to consider Democratic President Barack Obama’s nomination of appeals court Judge Merrick Garland for the vacant seat, an action with little precedent in U.S. history.

Democratic Senator Jeff Merkley of Oregon vowed to pursue a procedural hurdle called a filibuster for Trump’s nominee, meaning 60 votes would be needed in the 100-seat Senate unless its long-standing rules are changed. Trump’s fellow Republicans hold a 52-48 majority, meaning some Democratic votes would be needed.

“This is the seat that Mitch McConnell and team have stolen from President Obama. I won’t be complicit in this theft,” Merkley said in a statement. “We need to fight this Constitution-shredding gambit with everything we’ve got.”

‘CAREFUL CONSIDERATION’

On the Senate floor, McConnell had words of warning for Democrats, saying senators should respect Trump’s election victory and give the nominee “careful consideration followed by an up-or-down vote,” not a filibuster.

Trump, who took office on Jan. 20, said last week he would favor Senate Republicans eliminating the filibuster, a move dubbed the “nuclear option,” for Supreme Court nominees if Democrats block his pick.

White House spokesman Sean Spicer said of Democratic opposition: “It’s all about politics. It’s not about qualifications. The president has a right to have his nominees taken up.”

While not identifying the nominee, Spicer referred to the pick as “he” and said the selection came from the list of about 20 jurists recommended by conservative legal groups.

Senate Democratic leader Chuck Schumer said this month it is hard to imagine Trump picking a nominee who Democrats could support, adding he would “absolutely” fight to keep the seat vacant rather than let the Senate confirm a nominee deemed to be outside the mainstream.

Gorsuch, 49; Hardiman, 54; and Pryor, 51, possess strong conservative credentials.

Gorsuch joined an opinion in 2013 saying that owners of private companies can object on religious grounds to a provision of the Obamacare health insurance law requiring employers to provide coverage for birth control for women.

Gorsuch’s mother headed the Environmental Protection Agency under Republican President Ronald Reagan before quitting under pressure in 1983.

Hardiman has embraced a broad interpretation of the U.S. Constitution’s right to bear arms and has backed the right of schools to restrict student speech. Gun rights activists are eager for the Supreme Court to expand on a 2008 ruling that found for the first time that there is an individual right to bear arms for self-defense in the home.

Pryor has been an outspoken critic of the court’s 1973 landmark Roe v. Wade ruling legalizing abortion, calling it “the worst abomination of constitutional law in our history.” Conservatives are hoping the high court will back restrictions imposed on the procedure by some Republican-governed states.

Last year, the Supreme Court issued its strongest endorsement of abortion rights in more than two decades, striking down a Texas abortion law imposing strict regulations on doctors and facilities in a 5-3 ruling.

Pryor also joined a 2011 ruling favoring a transgender woman who said she was fired when she transitioned from male to female. The Supreme Court during its current term is due to decide a major transgender rights case for the first time. The justices have not yet heard arguments in the case, in which a Virginia public school district is fighting to prevent a female-born transgender high school student from using the boys’ bathroom.