WASHINGTON (Reuters) - The Republican-led Senate on Friday gave Donald Trump the biggest triumph of his young presidency, confirming his Supreme Court nominee over stout Democratic opposition and restoring a conservative majority on the highest U.S. judicial body.

The Senate, which last year refused to consider Democratic former President Barack Obama’s nominee to the court, voted 54-45 to approve Republican Trump’s pick, Colorado-based federal appeals court judge Neil Gorsuch, to the lifetime job. Three Democrats joined the Republicans in voting for Gorsuch.

Gorsuch’s confirmation ends the longest Supreme Court vacancy since 1862 during the American Civil War, with the court down a justice for almost 14 months since long-serving conservative Justice Antonin Scalia died on Feb. 13, 2016.

“Judge Gorsuch’s confirmation process was one of the most transparent and accessible in history, and his judicial temperament, exceptional intellect, unparalleled integrity and record of independence makes him the perfect choice to serve on the nation’s highest court,” Trump said in a statement.

“He’s going to make an incredible addition to the court,” Senate Majority Leader Mitch McConnell said on the Senate floor.

Illustrating the importance of the moment, Vice President Mike Pence served as the Senate’s presiding officer during the vote to confirm Gorsuch, who also worked in Republican former President George W. Bush’s Justice Department and is the son of the first woman to head the Environmental Protection Agency.

Republicans, possessing a 52-48 Senate majority, on Thursday overcame a ferocious Democratic effort to block a confirmation vote, resorting to a rule change known as the “nuclear option.”

“Today, for the first time in history, the theft of a Supreme Court seat has been completed, profoundly damaging the integrity of the court,” said Democratic Senator Jeff Merkley, referring to Republicans casting aside Obama’s nominee Merrick Garland, who would have tilted the court to the left for the first time in decades.

Merkley this week delivered a 15-1/2-hour Senate speech against Gorsuch.

The Senate’s approval of Gorsuch reinstates the nine-seat court’s 5-4 conservative majority, fulfilling an important Trump campaign promise.

Gorsuch, 49, was the youngest Supreme Court nominee since Republican President George H.W. Bush in 1991 picked Clarence Thomas, who was 43 at the time. Gorsuch could be expected to serve for decades, while Trump could make further appointments to the high court to make it even more solidly conservative because three of the eight justices are 78 or older.

Three Democratic senators up for re-election in 2018 in states won by Trump last year - Indiana’s Joe Donnelly, West Virginia’s Joe Manchin and North Dakota’s Heidi Heitkamp - voted for Gorsuch. Republican Senator Johnny Isakson missed the vote while recovering from back surgery.

Gorsuch’s confirmation gave a boost to Trump, showing he can get important agenda items through a Congress controlled by his fellow Republicans after the House of Representatives last month failed to pass healthcare overhaul legislation. Trump is planning major tax cut legislation as well.

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EXTRAORDINARY STEPS

Senate Republicans resorted to extraordinary steps to overcome Democratic opposition to Gorsuch, including changing long-standing Senate rules to prohibit the use of a procedural blockade called a filibuster for Supreme Court nominees. The rule change was dubbed the “nuclear option” because it was considered an extreme break from Senate tradition.

Democrats accused Gorsuch of being so conservative as to be outside the judicial mainstream, favoring corporate interests over ordinary Americans in legal opinions, and displaying insufficient independence from Trump.

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Gorsuch joins fellow conservatives Thomas, John Roberts, Samuel Alito and Anthony Kennedy on a court that also includes liberal justices Ruth Bader Ginsburg, Stephen Breyer, Sonia Sotomayor and Elena Kagan.

Trump has recorded accomplishments since taking office on Jan. 20, including a variety of unilateral executive actions such as moving to undo Obama’s climate change regulations.

But he has encountered trouble with other major initiatives. Courts blocked his executive action to stop people from several Muslim-majority countries from entering the United States. His administration also has faced questions about any role the president’s associates may have played in alleged Russian meddling in the 2016 U.S. presidential election to help Trump.

The rule change could make it easier for Trump to win confirmation of Supreme Court nominees as long as Republicans control the Senate, with Democrats left powerless to resist even if he gets a chance to replace the court’s senior liberal, 84-year-old Ginsburg, or the court’s swing vote, 80-year-old Kennedy, with more conservative replacements.

A conservative-majority court is more likely to support gun rights, abortion regulations, an expansive view of religious liberty and Republican-backed voting restrictions, while opposing curbs on political spending. The court also is likely to tackle transgender rights and union funding in coming years.

Among the groups congratulating Gorsuch on his confirmation were the U.S. Chamber of Commerce business lobbying group, the National Rifle Association gun rights group and anti-abortion activists.

Gorsuch will be sworn in on Monday in two different ceremonies, one at the court and one at the White House. He can then prepare for the court’s next round of oral arguments, starting on April 17. The court’s current term ends in June.

Gorsuch will participate in the justices’ private April 13 conference to consider taking new cases. There are appeals pending on expanding gun rights to include carrying concealed firearms in public, state voting restrictions that critics say are aimed at reducing minority turnout, and allowing business owners to object on religious grounds to providing gay couples certain services.

On April 19, the court will hear a case in which a church contends Missouri violated the U.S. Constitution’s guarantee of religious freedom by denying it funds for a playground project due to a state ban on aid to religious organizations. Gorsuch has ruled in favor of expansive religious rights during his decade as a judge.