U.S. Supreme Court Justice Antonin Scalia, a leading conservative voice on the high court, has died at the age of 79, a government source and a family friend told CNN on Saturday.
Scalia died in his sleep during a visit to Texas.
A government official said Scalia went to bed Friday night and told friends he wasn't feeling well. Saturday morning, he didn't get up for breakfast. And the group he was with for a hunting trip left without him.
Someone at the ranch went in to check on him and found him unresponsive.
The U.S. Marshals Service is not investigating Scalia's death, an official told CNN. They are helping to arrange for his body to be returned.
They were present because marshals sometimes help supplement security for traveling justices.
In a statement, Chief Justice John Roberts said he and other justices were "saddened" to hear of Scalia's passing.
"He was an extraordinary individual and jurist, admired and treasured by his colleagues," Roberts said. "His passing is a great loss to the court and the country he so loyally served. We extend our deepest condolences to his wife Maureen and his family."
Deputy White House Press Secretary Eric Schultz said President Barack Obama was informed of Scalia's passing on Saturday afternoon.
"The President and First Lady extend their deepest condolences to Justice Scalia's family. We'll have additional reaction from the President later today," Schultz said.
Scalia's death in an election year sets up a titanic confirmation tussle over his successor on the bench. The already challenging task of getting a Democratic president's nominee through a Republican-controlled Senate will made even more difficult as the fight over Scalia's replacement will emerge as a dominant theme of an already wild presidential election.
Soon after news of Scalia's death surfaced, Senate Majority Leader Mitch McConnell called for the vacancy to be filled
"The American people should have a voice in the selection of their next Supreme Court Justice. Therefore, this vacancy should not be filled until we have a new president," McConnell said in a statement.
Major presence on high court
Appointed to the court in 1986 by President Ronald Reagan, Scalia was a conservative icon who transformed the court by instilling in it his belief that judges should follow the precise words of the Constitution and not apply a modern interpretation.
He was the first justice of Italian-American heritage and passed through confirmation with a unanimous vote.
Scalia changed oral arguments as he became an active participant with tough questions for advocates.
He will be best known, perhaps, for his landmark decision District of Columbia v. Heller, holding that the Second Amendment protects the right to posses a firearm at home. He was a critic of Roe v. Wade and dissented in last term's same-sex marriage cases.
He wrote a stinging dissent in the same-sex marriage case Obergefell v. Hodges, calling the decision a "threat to American democracy."
He believed that marriage should be decided by the people not the courts, and he was concerned that some members of the bench might determine that the death penalty is unconstitutional.
Scalia caused a stir as recently as December when he made controversial comments during a hearing about the future of a program at the University of Texas that takes race into consideration as one factor of admissions.
Scalia pushed a point that had been made in some friend of the court briefs filed in the case. It concerns a theory called "Mismatch" popularized by authors Stuart Taylor Jr. and Richard Sander that suggests affirmative action programs don't always benefit minorities.
Although Roberts had mentioned the theory in a different case in 2013, Scalia's language was blunt.
"There are those who contend that it does not benefit African-Americans to get them into the University of Texas, where they do not do well, as opposed to having them go to a less-advanced school, a slower-track school where they do well," he said.
"One of the briefs pointed out that most of the black scientists in this country don't come from schools like the University of Texas," he said.
Conservative in thought, not in personality
The jaunty jurist was able to light up, or ignite, a room with his often brash demeanor and wicked sense of humor, grounded always in a profound respect for American law and its constitutional traditions.
"What can I say," was a favorite phrase of the man colleagues knew as "Nino." As it turned out, quite a lot.
"Justice Scalia had an irrepressibly pugnacious personality," said Edward Lazarus, a former Supreme Clerk law clerk who wrote about the experience in "Closed Chambers."
"And even in his early years of the Court, that came out at oral argument when he was the most aggressive questioner. And behind the scenes, where the memos he would write -- what were called 'Ninograms' -- inside the court had a real galvanizing effect on the debate among the justices."
A sharp mind combined with a sharp pen allowed Scalia to make his point, both to the pleasure and disappointment of his colleagues and the public.
"He could be belligerent, he was obviously very candid about he felt about things," said Joan Biskupic, a USA Today reporter who wrote a biography of Scalia. "He loved to call it as he saw it, completely not politically correct. In fact, he prided himself on not being PC on the bench in court."
His New York and Mediterranean roots -- "I'm an Italian from Queens" he was fond of saying -- helped fashion a love of words and debate, combining street smarts with a well-calculated conservative view of the law and its limits on society.
"He was very good with audiences that weren't predisposed to like him," said Paul Clement, a former Scalia law clerk. "He was incredibly disarming and charming in his own way."
He was a Catholic who regularly attended Red Mass before each term. He and his wife had nine children and 28 grandchildren.
His best friend on the bench was Justice Ruth Bader Ginsburg, who he called his "best buddy" on the court. Last winter, they appeared together in a wide-ranging discussion on Constitutional issues.
"Why don't you call us the odd couple?" Scalia said.
Former CNN Supreme Court producer Bill Mears researched and wrote much of this obituary prior to Scalia's death. CNN's Steve Almasy and Stephen Collinson contributed to this report.