By Lawrence Hurley and Andrew Chung
WASHINGTON (Reuters) - Democrats on Monday amassed enough support to block a U.S. Senate confirmation vote on President Donald Trump's Supreme Court nominee, Neil Gorsuch, but Republicans vowed to change the Senate rules to ensure the conservative judge gets the lifetime job.
As the Judiciary Committee moved toward sending Gorsuch's nomination to the full Senate, Senator Christopher Coons became the 41st Democrat to announce support for a procedural hurdle requiring a super-majority of 60 votes in the 100-seat Senate to allow a confirmation vote.
But Republican Senate leaders insist Gorsuch will be confirmed on the Senate floor on Friday regardless of what the Democrats do, even if they have to change long-standing Senate rules.
Coons told fellow members of the Judiciary Committee it would be "tragic" if Republicans change Senate rules to end the filibuster for Supreme Court nominees. "The principles that have defined the Senate are crumbling, and we are poised to hasten that this week," Coons said.
Democratic Senators Dianne Feinstein, the committee's top Democrat, and Mark Warner, not a member of the panel, also announced opposition to Gorsuch on Monday and support for a filibuster.
The panel began its meeting and was set to vote later on Monday after its members spoke on Gorsuch's nomination. Republicans hold a 11-9 majority on the committee, which held a four-day confirmation hearing last month, and control the Senate by a 52-48 margin.
If the Democrats mount a successful filibuster, Senate Majority Leader Mitch McConnell would be expected to force a confirmation vote by having the Senate change its rules and allow for a simple majority vote for confirmation of Supreme Court justices, a move sometimes called the "nuclear option" that Trump has urged.
Senate confirmation of Gorsuch, 49, would restore the nine-seat high court's conservative majority, fulfilling one of Trump's top campaign promises. Trump in January nominated Gorsuch, a conservative appeals court judge from Colorado, to the lifetime job as a justice.
Gorsuch was nominated to fill a vacancy created by the February 2016 death of conservative Justice Antonin Scalia.
The actual confirmation vote would be by a simple majority if the filibuster is stopped. To date, three Democrats have come out in support of Gorsuch, and the Republicans would have needed to secure eight Democratic votes to kill a filibuster.
Democratic Senator Michael Bennet, who represents Gorsuch's home state of Colorado and introduced the nominee during his confirmation hearing, said he would oppose the filibuster effort but did not take a position on whether to vote in favor of the judge.
The committee's chairman, Republican Chuck Grassley, defended Gorsuch as a mainstream jurist worthy of confirmation despite the complaints of many Democrats, and that "there isn't a whole lot of mystery" that the panel will approve the nomination.
Feinstein said this was not a "routine nomination," noting that the Republican-led Senate last year flatly refused to consider Democratic former President Barack Obama's nomination of appellate judge Merrick Garland to fill the same high court vacancy.
"There was simply no reason that the nomination of Judge Garland could not proceed, other than to deny the then-president of the United States, President Barack Obama, the ability to fill the seat," Feinstein said.
Feinstein criticized Gorsuch's rulings in cases involving a fired truck driver and an autistic child and faulted his actions as a lawyer in Republican former President George W. Bush's Justice Department regarding detainee interrogation techniques critics called torture.
Feinstein also said she was disturbed by the millions of dollars of "dark money" from anonymous donors backing advertising and political advocacy by conservative groups to help Gorsuch win confirmation.
'I HATE THAT'
The 60-vote super-majority requirement over the decades has forced the Senate to try to achieve bipartisanship in legislation and in presidential appointments.
Senator Lindsey Graham, a Republican committee member, expressed regret that his party would be forced to change the Senate rules and said the "damage done to the Senate's going to be real."
"If we have to, we will change the rules, and it looks like we're going to have to. I hate that. I really, really do," Graham said.
Democrats have accused Gorsuch of being insufficiently independent of Trump, evading questions on key Supreme Court rulings of the past including on abortion and political spending, and favoring corporate interests over ordinary Americans.
Committee Democratic Senator Patrick Leahy said Gorsuch was "excruciatingly evasive" during his confirmation hearing. He called Gorsuch's approach to responding to the committee "patronizing. It's a disservice to the American people and a blight on the confirmation process." Leahy's office made clear he would back a filibuster.
"Over the last couple months, the nominee's opponents have tried to find fault with him. That fault will not stick," Grassley said.
"Judge Gorsuch is by any measure a superbly qualified nominee," added Senator Orrin Hatch, a committee Republican. "He will be impartial, fair and open-minded."
While Gorsuch's opponents would fight a Senate rule change, it was the Democrats who in 2013 changed the Senate rules to limit filibusters after Republicans used the procedure against appeals court nominees selected by Obama. The Senate, then led by Democrats, barred filibusters for executive branch nominees and federal judges aside from Supreme Court justices. Even if Republicans do change the rules, legislation, as opposed to appointments, would still need to meet a 60-vote threshold.
(Reporting by Lawrence Hurley; Additional reporting by Susan Heavey and Doina Chiacu; Editing by Will Dunham)