WASHINGTON — President Donald Trump is expected to announce Saturday that he is nominating Judge Amy Coney Barrett to the Supreme Court as he aims to put a historic conservative stamp on the high court before the election.

Trump said Friday he had made up his mind and it was “very exciting,” without giving away the name, aiming to maintain some suspense around his personal announcement. But the White House indicated to congressional Republicans and outside allies that the pick was Barrett.

“Well I haven’t said it was her, but she’s outstanding,” Trump said of the Indiana federal judge.

The likely shift in the court’s makeup — from Ginsburg, a liberal icon, to an outspoken conservative — would be the sharpest ideological swing since Clarence Thomas replaced Justice Thurgood Marshall nearly three decades ago.