US President Donald Trump has nominated Brett Kavanaugh for the Supreme Court, setting the stage for a bruising confirmation battle.
In a primetime announcement at the White House, Mr Trump praised his pick as a "brilliant jurist".
The nominee, a District of Columbia appeals court judge, is a former adviser to ex-President George W Bush.
The decision has far-reaching implications for America on everything from abortion to guns to immigration.
This is Mr Trump's second appointment to the highest court in the land, potentially allowing him to shape the US for a generation after he leaves office.
The president said: "Judge Kavanaugh has impeccable credentials, unsurpassed qualifications and a proven commitment to equal justice under the law."
Mr Trump added: "He is a brilliant jurist with a clear and effective writing style, universally regarded as one of the finest and sharpest legal minds of our time."
With reality television-style suspense, the president had kept everyone guessing up until the last moment.
The appointee would replace Justice Anthony Kennedy, 81, who announced last month that he will retire this summer.
At Monday night's announcement in the East Room, Judge Kavanaugh, 53, said: "Mr President, thank you. Throughout this process I have witnessed firsthand your appreciation for the vital role of the American judiciary.
"No president has ever consulted more widely, or talked with more people from more backgrounds to seek input abut a Supreme Court nomination.
"I am grateful to you and I am humbled by your confidence in me."
Who is Judge Kavanaugh?
He has served since 2006 on the influential US Court of Appeals for the District of Columbia Circuit and was formerly a White House aide under George W Bush.
He previously worked for Kenneth Starr, the independent counsel who investigated Democratic former president Bill Clinton in the 1990s.
A Yale graduate and devout Catholic who went to a Jesuit high school, he once clerked for Justice Kennedy, the man he would replace.
Judge Kavanaugh recently voiced disagreement with a court decision allowing an undocumented teenage immigrant to have an abortion.
He wrote a Minnesota law review article in 2009 arguing that presidents should be shielded from criminal investigations and civil lawsuits while in office.
Analysts say that could have weighed in his favour with the White House, given that the Supreme Court may at some point be asked to rule on matters arising from Special Counsel Robert Mueller's ongoing Russia-related investigation.
What's at stake?
The US Supreme Court is the ultimate arbiter on contentious laws and disputes between states and the federal government.
It rules on such issues as abortion, the death penalty, voter rights, immigration policy, campaign finance and racial bias in policing.
Each of the nine justices holds a lifetime appointment. Judge Kavanaugh is relatively young, meaning he could serve for decades to come.
His appointment will not change the ideological tilt of a court that already has a 5-4 conservative majority, but he could nevertheless shift the bench further right.
Justice Kennedy sometimes sided with the court's liberal justices on divisive social issues. But Judge Kavanaugh may not be so accommodating.
Neil Gorsuch, 50, who was appointed by Mr Trump last year, is already one of the court's most conservative justices.