WASHINGTON (Reuters) - Donald Trump reveled in the biggest political victory of his presidency at a White House ceremony on Monday in which his Supreme Court pick Neil Gorsuch was sworn in, poised to make an instant impact on a court once again dominated by conservatives. Trump was able to fulfill a top campaign promise when the Republican-led U.S. Senate voted to confirm the conservative Colorado-based federal appeals court judge to the lifetime job on Friday despite vehement Democratic opposition. With Gorsuch aboard, the court has five conservative justices and four liberals, a majority that could be pivotal in deciding a range of issues including abortion, gun control, the death penalty, presidential powers, political spending, environmental regulation and religious rights.  Standing in the White House Rose Garden under bright sunshine on a warm spring day, Trump tied the occasion to the political aims of his administration, as the eight other members of the nation’s highest court looked on. “Together we are in a process of reviewing and renewing and also rebuilding our country,” Trump told an audience that included conservative activists and administration officials. “A new optimism is sweeping across our land and a new faith in America is filling our hearts and lifting our sights.” Gorsuch filled a vacancy that had lingered for nearly 14 months after conservative Justice Antonin Scalia’s February 2016 death. Gorsuch’s judicial oath was administered by Justice Anthony Kennedy, for whom Gorsuch worked as a clerk as a young lawyer. Gorsuch becomes the first justice to serve alongside a former boss. Trump made a point of thanking Senate Majority Leader Mitch McConnell for his role in winning confirmation. McConnell last week led the effort to change long-standing Senate rules in order to end a Democratic blockade of Gorsuch’s nomination. Under McConnell’s leadership, the Senate last year refused to consider Democratic former President Barack Obama’s nomination of Merrick Garland to replace Scalia, an appointment that would have tilted the court to the left for the first time in decades. “I’ve always heard that the most important thing that a president of the United States does is appoint people, hopefully great people like this appointment, to the United States Supreme Court,” Trump said. “He will decide cases not based on his personal preferences but based on a fair and objective reading of the law,” Trump said of Gorsuch. During last year’s presidential campaign, Trump pledged to pick a justice who would overturn the landmark 1973 Supreme Court Roe v. Wade ruling that legalized abortion. During his Senate confirmation hearing, Gorsuch declined to answer about whether Roe v. Wade and other important court precedents were properly decided. “To the American people, I am humbled by the trust placed in me today,” Gorsuch said, with his wife Louise and the Republican president standing behind him. “I will never forget that to whom much is given, much will be expected. And I promise you that I will do all my powers permit to be a faithful servant of the Constitution and laws of this great nation.” Those attending included liberal Justice Ruth Bader Ginsburg, who called Trump “a faker” during the presidential campaign but later said she regretted the remark. Trump at the time called for her resignation, saying her “mind is shot.”  Scalia’s widow, Maureen, also attended. Gorsuch earlier in the day took his separate constitutional oath, administered by Chief Justice John Roberts, in a private ceremony at the Supreme Court with the other justices. Gorsuch, 49, could serve for decades. Trump may be able to make further appointments to make the court even more solidly conservative, with three justices 78 or older: Ginsburg, 84; fellow liberal Stephen Breyer, 78; and conservative swing vote Kennedy, 80. Gorsuch will take part in the court’s next round of oral arguments, starting on April 17. They include a religious rights case on April 19 in which a Missouri church is objecting to being denied state funds for a playground project due to a state ban on providing public money to religious organizations. Gorsuch can be expected to have an immediate impact on the court. He takes part on Thursday in the justices’ private conference to decide which cases to take up. Among cases up for discussion is one in which gun activists are seeking to expand gun rights to include carrying concealed firearms in public. Another is a bid to reinstate Republican-backed North Carolina voting restrictions that a lower court found were intended to suppress black voter turnout. A third concerns whether a Christian bakery owner can object on religious grounds to making a cake for a gay couple.  With Gorsuch sworn in, his new colleagues could decide to hear new arguments in their next term, starting in October, in cases argued during their current term in which they may have been split 4-4 and did not yet decide. 