President Barack Obama has nominated veteran appeals court judge Merrick Garland to be the next US Supreme Court Justice.
The Supreme Court vacancy follows the death of Antonin Scalia last month.
Judge Garland, 63, is viewed as a moderate and has won praise from senior Republican figures.
The appointment has to be ratified by the Senate, but its Republican majority has vowed to block a vote on any Supreme Court nominee from Mr Obama.
Republicans have called on the president to leave the nomination to his successor, who will be elected in November.
The death of Justice Scalia, a staunch conservative, left the nine-member Supreme Court evenly divided between conservatives and liberals.
t also set off a battle in a presidential election year over Justice Scalia’s successor.
Urging the Senate to support Mr Garland, the US president said: “He is the right man for the job. He deserves to be confirmed”.
President Obama said Mr Garland – chief judge of the Washington appeals court and a former prosecutor – enjoyed respect from Democrats and Republicans alike.
Announcing the nomination in the White House Rose Garden, Mr Obama praised Mr Garland’s decency, integrity and even-handedness during his long career in public service, and described him as an exemplary judge.
Mr Garland was prepared to serve on the court immediately, he said.
President Obama expressed hope that Republicans would act in a bipartisan spirit and give Mr Garland a “fair hearing”.
The nomination was the “greatest honour of my life”, Mr Garland said.
Mr Garland was appointed by Democratic President Bill Clinton in 1997, winning confirmation in a 76-23 Senate vote, and served in the Justice Department during the Clinton administration prior to that.
‘If not Garland, who?’
Republicans again stressed they would defer action on a nomination to the Supreme Court until after the election.
Senate Republican majority leader Mitch McConnell said the American people should have a voice in filling the vacancy. He also accused Mr Obama of making the nomination “in order to politicise it for purposes of the election”.
Another Republican – Paul Ryan, the Speaker of the House of Representatives – said this had never been about who the nominee is.
“It is about a basic principle. Under our Constitution, the president has every right to make this nomination, and the Senate has every right not to confirm a nominee.”
Senate Minority Leader Harry Reid said Republicans must act on the president’s choice.
And a senior Democratic Senator, Chuck Schumer, described Merrick Garland as a “bipartisan choice”.
He asked: “If the Republicans can’t support him, who can they support?”