The US Senate has confirmed Amy Coney Barrett to the Supreme Court delivering Donald Trump a huge victory a week before the presidential election.
The vote was a formality, with senators divided almost entirely along party lines, voting 52 to 48 with just one Republican breaking ranks.
Barrett, 48, becomes only the fifth woman to sit on the supreme court.Her appointment seals for the foreseeable future a 6-3 conservative majority on the top US judicial body.
To date, Trump has placed three conservative justices on the court, albeit in highly contentious and controversial circumstances.
For US democracy, the confirmation gives the conservative justices the upper hand on issues such as abortion, same-sex marriage and the climate crisis – areas where public opinion is firmly in favour of progressive change.
Democratic presidential candidate Joe Biden called the move rushed and unprecedented.
During a campaign stop in Pennsylvania, he tweeted: “More than 60 million Americans have already voted. They deserve to have their voices heard on who replaced Justice Ginsburg.”
Following the vote, a swearing-in ceremony was held at the White House. Trump introduced Barrett saying that her addition to the court carried forward “the cause of freedom”.
Democrats fear Judge Barrett's confirmation to the lifelong post will favour Republicans in politically sensitive cases that reach America's top court for potentially decades to come.
Supreme Court justices take two oaths before beginning their job - the constitutional oath and the judicial oath.
Supreme Court Justice Clarence Thomas, a conservative, administered the oath of office to his new colleague.
Justice Barrett said afterwards: "A judge declares independence not only from the Congress and the president, but also from the private beliefs that might otherwise move her.
"The judicial oath captures the essence of the judicial duty: the rule of law must always control."
She thanked the Senate for the confidence they placed in her, ignoring the inconvenient truth that half the political composition of the chamber had turned its back on her.
Chuck Schumer, the top Democrat in the Senate cast Barrett’s confirmation as one of the “darkest days in the 231-year history” of the Senate.
Addressing his Republican peers, he said: “You may get Amy Coney Barrett on to the supreme court but you will never, never get your credibility back.”
Barrett, a favourite of Christian conservatives, signed a 2006 newspaper ad that called for the overturning of Roe v Wade, the 1973 ruling that legalised abortion, and called its legacy “barbaric”. She did not disclose the ad to the Senate.
Justice Barrett could cast a decisive vote in a number of looming cases, including a Trump-backed challenge to the Affordable Care Act, also known as Obamacare, on 10 November.
A previous ruling by Justice Barrett on Obamacare has alarmed advocates of the healthcare programme.
Trump has also said he expects the court to decide the outcome of a disputed election, as it did in 2000, and wants Barrett on the bench for any election-related cases.
Democrats have threatened to retaliate for Judge Barrett's appointment by court-packing - which would entail expanding the number of justices on the nine-seat Supreme Court - if they win the White House and control of the Senate next week.