United States President Donald Trump on Saturday nominated Amy Coney Barrett to the Supreme Court, and she pledged to become a justice in the mold of the late staunch conservative Antonin Scalia, setting another milestone in Trump’s rightward shift of the top US judicial body.

Trump’s announcement during a flag-festooned White House Rose Garden ceremony — with Barrett, 48, by his side and her seven children on hand — sets off a scramble by Senate Republicans to confirm her as the president has requested before Election Day in five and a half weeks, when he will be seeking a second term in office.

If confirmed by the Senate to replace liberal icon Ruth Bader Ginsburg, who died at age 87 on September 18, Barrett would become the fifth woman ever to serve on the court and would push its conservative majority to a commanding 6-3.

Like Trump’s two other appointees, Neil Gorsuch in 2017 and Brett Kavanaugh in 2018, Barrett is young enough that she could serve for decades in the lifetime job, leaving a lasting conservative imprint. Barrett is the youngest Supreme Court nominee since conservative Clarence Thomas, who was 43 in 1991.

Scalia, who died in 2016, was one of the most influential conservative justices in recent history. Barrett previously served as a clerk for Scalia on the high court and described him as her mentor, citing his “incalculable influence” on her life.

“His judicial philosophy is mine too: a judge must apply the law as written. Judges are not policymakers,” Barrett said.

On the court, Scalia voted to curb abortion rights, dissented when the court legalised gay marriage — he called it a “judicial putsch” — and backed broad gun rights, among other positions.

With Trump’s fellow Republicans holding a 53-47 Senate majority, confirmation appears certain, although Democrats may try to make it as difficult as possible.

An emboldened Supreme Court conservative majority could shift the US to the right on hot-button issues by, among other things, curbing abortion rights, expanding religious rights, striking down gun control laws, halting the expansion of LGBT rights, and endorsing new restrictions on voting rights.