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 earlier 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.
It 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”.
Over to the Republicans – Anthony Zurcher, BBC News, Washington DC
There were a lot of possible strategies being suggested as President Obama considered who would be his Supreme Court nominee. Would he opt for a young, outspoken liberal to rally his party’s base and enact a generational ideological change on the court? Would he chose an underrepresented ethnicity or a woman that would force Republicans to risk angering some key voting bloc if they failed to confirm?
In the end Mr Obama chose accommodation by picking an older centrist in appellate court judge Merrick Garland.
It could be that Mr Obama still thinks there’s a chance of Senate confirmation for a respected moderate. Maybe he thinks voters will be angered if the Senate rejects even the most uncontroversial choice.
Or perhaps Mr Garland was the best, most qualified candidate who would agree to go along with what will likely be a bruising, probably futile nomination process – a sacrificial lamb offered up in acknowledgment of a dire political reality.
One way or the other it’s the Republicans’ move now. They can accept Mr Garland or gamble that there won’t be a new Democratic president next year who is itching for a fight.
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.
Supreme Court Nominee
- Age: 63
- Education: Harvard College and Law School
- Current Job: Chief Judge, federal appeals court of Washington DC
- Notable: Supervised investigations into the 1995 Oklahoma City bombing
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 Merrick 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.