President Donald Trump has nominated Neil Gorsuch, a fast-rising conservative judge, to the Supreme Court, setting up a clash with Democrats.
At 49, he is the youngest nominee in 25 years and could help shape America's legal landscape for decades to come.
He is known on the Denver-based 10th Circuit Court of Appeals for advocacy for court review of government regulations, defence of religious freedom and scepticism toward law enforcement.
"Judge Gorsuch has outstanding legal skills, a brilliant mind, tremendous discipline and has earned bipartisan support," Mr Trump declared, announcing the nomination in his first televised prime-time address from the White House.
The nomination was praised by conservatives wary of Mr Trump's own fluid ideology.
If confirmed by the Senate, he will fill the seat left vacant by the death last year of Antonin Scalia, long the right's most powerful voice on the high court.
Judge Gorsuch thanked Mr Trump for entrusting him with "a most solemn assignment".
Outlining his legal philosophy, he said: "It is the rule of judges to apply, not alter, the work of the people's representatives. A judge who likes every outcome he reaches is very likely a bad judge."
Some Democrats, still smarting over Mr Trump's unexpected victory in the presidential election, had vowed to mount a vigorous challenge to nearly any nominee to what they view as the court's "stolen seat".
President Barack Obama had nominated US Circuit Court Judge Merrick Garland for the vacancy, but Senate Republicans refused to consider the choice, saying the seat should be filled only after the November election.
Senate Democratic leader Charles Schumer said he has "serious doubts" that Judge Gorsuch is within what Democrats consider the legal mainstream.
For some Republicans, the prospect of filling one or more Supreme Court seats over the next four years has helped ease their concerns about Mr Trump's experience and temperament.
Three justices are in their late 70s and early 80s, and a retirement would offer Mr Trump the opportunity to cement conservative dominance of the court for many years.
The nominee's writings outside the court offer insight into his conservative leanings. He lashed out at liberals in a 2005 opinion piece for National Review, written before he became a federal judge.
"American liberals have become addicted to the courtroom, relying on judges and lawyers rather than elected leaders and the ballot box, as the primary means for effecting their social agenda on everything from gay marriage to assisted suicide to the use of vouchers for private-school education," he wrote.
Like the other eight justices on the court, he has an Ivy League law degree.
The Colorado native earned his bachelor's degree from Columbia University in three years, then a law degree from Harvard and a philosophy degree at Oxford University.
He served for two years in George W Bush's Department of Justice, and his mother, Anne Gorsuch Burford, was head of the Environmental Protection Agency in the Reagan administration.
Judge Gorsuch was among the 21 possible choices for the court Mr Trump released during the campaign.