TEXAS - U.S. Supreme Court Justice Antonin Scalia 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.
President Barack Obama says he plans to nominate a replacement for Supreme Court Justice Antonin Scalia.
"I plan to fulfill my constitutional responsibilities to nominate a successor in due time," Obama said from his presidential trip to California.
"There will be plenty of time for me to do so and for the Senate to fulfill its responsibility to give that person a fair hearing and a timely vote." Obama said Scalia had a "brilliant legal mind with an energetic style, incisive wit and colorful opinions."
"He influenced a generation of judges and lawyers and students and profoundly shaped the legal landscape," Obama said.
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."
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.
"His departure leaves a huge political fight in the offing because this is a court with five Republican appointees (and) four Democratic appointees," CNN Senior Legal Analyst Jeffrey Toobin said.
Major presence on high court
The first Italian-American to sit on the nation's highest court, Scalia was a conservative in thought, but 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."
Following the news of Justice Scalia's passing, Texas Governor Abbott released the following statement:
Justice Antonin Scalia was a man of God, a patriot, and an unwavering defender of the written Constitution and the Rule of Law. He was the solid rock who turned away so many attempts to depart from and distort the Constitution. His fierce loyalty to the Constitution set an unmatched example, not just for judges and lawyers, but for all Americans. We mourn his passing, and we pray that his successor on the Supreme Court will take his place as a champion for the written Constitution and the Rule of Law. Cecilia and I extend our deepest condolences to his family, and we will keep them in our thoughts and prayers.