WASHINGTON, DC - APRIL 17:  Supreme Court Justice Antonin Scalia waits for the beginning of the taping of "The Kalb Report" April 17, 2014 at the National Press Club in Washington, DC. The Kalb Report is a discussion of media ethics and responsibility at the National Press Club held each month. (Photo by Alex Wong/Getty Images)
WASHINGTON, DC - APRIL 17: Supreme Court Justice Antonin Scalia waits for the beginning of the taping of "The Kalb Report" April 17, 2014 at the National Press Club in Washington, DC. The Kalb Report is a discussion of media ethics and responsibility at the National Press Club held each month. (Photo by Alex Wong/Getty Images)
PHOTO: Alex Wong/Getty Images
Now playing
02:58
Supreme Court Justice Antonin Scalia dead at 79
obama scalia replacement options supreme court brown dnt tsr_00004310.jpg
obama scalia replacement options supreme court brown dnt tsr_00004310.jpg
PHOTO: Getty Images
Now playing
01:56
Obama's options to replace Justice Antonin Scalia
mcconnell cornyn wont meet with obama supreme court nominee sot_00001614.jpg
mcconnell cornyn wont meet with obama supreme court nominee sot_00001614.jpg
Now playing
00:50
Senate GOP: We will not meet with Obama's nominee (2016)
US President Barack Obama speaks to the media during a bi-lateral meeting with King Abdullah II of Jordan in the Oval Office at the White House February 24, 2016 in Washington, DC.
US President Barack Obama speaks to the media during a bi-lateral meeting with King Abdullah II of Jordan in the Oval Office at the White House February 24, 2016 in Washington, DC.
PHOTO: Mark Wilson/Getty Images
Now playing
01:35
Obama responds to GOP's plans to block SCOTUS nominee
The Courtroom of the Supreme Court showing Associate Justice Antonin Scalia
The Courtroom of the Supreme Court showing Associate Justice Antonin Scalia's Bench Chair and the Bench in front of his seat draped in black following his death on February 13, 2016.
PHOTO: Supreme Court of the United States
Now playing
01:28
Poll: Obama should nominate new justice
WASHINGTON, DC - FEBRUARY 14:  An American flag flies at half mast following the death of Supreme Court Justice Antonin Scalia at the U.S. Supreme Court, February 14, 2016 in Washington, DC. Supreme Court Justice Antonin Scalia was at a Texas Ranch Saturday morning when he died at the age of 79. (Drew Angerer/Getty Images)
WASHINGTON, DC - FEBRUARY 14: An American flag flies at half mast following the death of Supreme Court Justice Antonin Scalia at the U.S. Supreme Court, February 14, 2016 in Washington, DC. Supreme Court Justice Antonin Scalia was at a Texas Ranch Saturday morning when he died at the age of 79. (Drew Angerer/Getty Images)
PHOTO: Drew Angerer/Getty Images North America/Getty Images
Now playing
01:47
Sources: White House vetting Jane Kelly for Supreme Court
US President Barack Obama speaks to the media during a bi-lateral meeting with King Abdullah II of Jordan in the Oval Office at the White House February 24, 2016 in Washington, DC.
US President Barack Obama speaks to the media during a bi-lateral meeting with King Abdullah II of Jordan in the Oval Office at the White House February 24, 2016 in Washington, DC.
PHOTO: Mark Wilson/Getty Images
Now playing
03:26
Source: Obama vetting GOP governor as potential nominee
supreme court justice thomas speaks origwx bw_00000000.jpg
supreme court justice thomas speaks origwx bw_00000000.jpg
Now playing
01:58
Hear Justice Thomas break his ten year silence (2016)
Supreme Court Justices Antonin Scalia (L) and Ruth Bader Ginsburg (R) wait for the beginning of the taping of "The Kalb Report" April 17, 2014 at the National Press Club in Washington, DC.
Supreme Court Justices Antonin Scalia (L) and Ruth Bader Ginsburg (R) wait for the beginning of the taping of "The Kalb Report" April 17, 2014 at the National Press Club in Washington, DC.
PHOTO: Alex Wong/Getty Images
Now playing
02:00
The Supreme Court's odd couple
SCOTUS Scalia senate hearing GOP newday_00012524.jpg
SCOTUS Scalia senate hearing GOP newday_00012524.jpg
PHOTO: CSPAN
Now playing
01:58
Senators break ranks over SCOTUS hearing
PHOTO: pool
Now playing
01:57
Obama joins crowd paying respect to Antonin Scalia
Justice Scalia funeral basilica _00003619.jpg
Justice Scalia funeral basilica _00003619.jpg
PHOTO: CNN
Now playing
01:15
Thousands attend Justice Scalia's funeral
384802 07: (FILE PHOTO) This undated file photo shows Justice Antonin Scalia of the Supreme Court of the United States in Washington, DC. (Photo by Liaison)
384802 07: (FILE PHOTO) This undated file photo shows Justice Antonin Scalia of the Supreme Court of the United States in Washington, DC. (Photo by Liaison)
PHOTO: Hulton Archive/Getty Images
Now playing
04:56
Antonin Scalia known for sharp mind and brash demeanor
WASHINGTON, DC - APRIL 17:  Supreme Court Justice Antonin Scalia waits for the beginning of the taping of "The Kalb Report" April 17, 2014 at the National Press Club in Washington, DC. The Kalb Report is a discussion of media ethics and responsibility at the National Press Club held each month. (Photo by Alex Wong/Getty Images)
WASHINGTON, DC - APRIL 17: Supreme Court Justice Antonin Scalia waits for the beginning of the taping of "The Kalb Report" April 17, 2014 at the National Press Club in Washington, DC. The Kalb Report is a discussion of media ethics and responsibility at the National Press Club held each month. (Photo by Alex Wong/Getty Images)
PHOTO: Alex Wong/Getty Images
Now playing
02:58
Supreme Court Justice Antonin Scalia dead at 79
US Supreme Court Justice Antonin Scalia speaks during the American Bar Association (ABA) 59th annual "Antitrust Law Spring" meeting in Washington, DC, on March 31, 2011. AFP Photo/Jewel Samad (Photo credit should read JEWEL SAMAD/AFP/Getty Images)
US Supreme Court Justice Antonin Scalia speaks during the American Bar Association (ABA) 59th annual "Antitrust Law Spring" meeting in Washington, DC, on March 31, 2011. AFP Photo/Jewel Samad (Photo credit should read JEWEL SAMAD/AFP/Getty Images)
PHOTO: JEWEL SAMAD/AFP/Getty Images
Now playing
03:05
Obama: Antonin Scalia 'a larger than life presence'
PHOTO: Paul Sancya/AP and Alex Wong/Getty Images
Now playing
00:44
Do GOP rivals agree with Obama on Scalia replacement?
Justices of the US Supreme Court sit for their official group photo at the Supreme Court in Washington, DC, on June 1, 2017. 
Seated (L-R): Associate Justices Ruth Bader Ginsburg and Anthony M. Kennedy, Chief Justice of the US John G. Roberts, Associate Justices Clarence Thomas and Stephen Breyer. Standing (L-R): Associate Justices Elena Kagan, Samuel Alito Jr., Sonia Sotomayor and Neil Gorsuch. / AFP PHOTO / SAUL LOEB        (Photo credit should read SAUL LOEB/AFP/Getty Images)
Justices of the US Supreme Court sit for their official group photo at the Supreme Court in Washington, DC, on June 1, 2017. Seated (L-R): Associate Justices Ruth Bader Ginsburg and Anthony M. Kennedy, Chief Justice of the US John G. Roberts, Associate Justices Clarence Thomas and Stephen Breyer. Standing (L-R): Associate Justices Elena Kagan, Samuel Alito Jr., Sonia Sotomayor and Neil Gorsuch. / AFP PHOTO / SAUL LOEB (Photo credit should read SAUL LOEB/AFP/Getty Images)
PHOTO: SAUL LOEB/AFP/Getty Images
Now playing
01:16
How are Supreme Court justices chosen?
David Axelrod Justice Scalia Kagan newday_00005626.jpg
David Axelrod Justice Scalia Kagan newday_00005626.jpg
PHOTO: CNN
Now playing
00:59
Axelrod: Scalia lobbied for friend to make bench
PHOTO: Youtube/ American Constitution Society
Now playing
02:00
2007: Democrat vows to block Bush Supreme Court nominee
Supreme Court Justice Antonin Scalia waits to be introduced to speak on October 2, 2012, in Washington, D.C.
Supreme Court Justice Antonin Scalia waits to be introduced to speak on October 2, 2012, in Washington, D.C.
PHOTO: Alex Wong/Getty
Now playing
02:17
The fight for Justice Scalia's replacement is on
Marco Rubio Antonin Scalia Supreme Court nomination sotu_00002014.jpg
Marco Rubio Antonin Scalia Supreme Court nomination sotu_00002014.jpg
Now playing
01:41
Rubio: Next President should appoint Scalia replacement
obama sessions supreme court appointment_00002908.jpg
obama sessions supreme court appointment_00002908.jpg
Now playing
00:48
Senator vows opposition to Obama's Scalia successor
scalia on death penalty torture piers intv_00022630.jpg
scalia on death penalty torture piers intv_00022630.jpg
Now playing
03:53
2012: Justice Antonin Scalia on death penalty, torture
scalia burning flag piers intv_00003907.jpg
scalia burning flag piers intv_00003907.jpg
Now playing
01:24
Antonin Scalia: Flag burning 'a form of expression'
scalia roe v wade piers intv_00030419.jpg
scalia roe v wade piers intv_00030419.jpg
Now playing
04:07
2012: Scalia: Constitution says nothing about abortion
Now playing
02:25
Ginsburg and Scalia's wild adventures
Supreme Court Justice Antonin Scalia waits for the beginning of the taping of "The Kalb Report" April 17, 2014 at the National Press Club in Washington, DC.
Supreme Court Justice Antonin Scalia waits for the beginning of the taping of "The Kalb Report" April 17, 2014 at the National Press Club in Washington, DC.
PHOTO: Alex Wong/Getty Images
Now playing
01:15
Supreme Court Justice makes controversial comments
PHOTO: CNN
Now playing
00:41
Who would Trump put on the court? (February 2016)
SOTU Tapper: State of the Cartoonion: Scalia burns_00010012.jpg
SOTU Tapper: State of the Cartoonion: Scalia burns_00010012.jpg
Now playing
01:22
2015: Scalia's carefully crafted verbal burns

Story highlights

U.S. Supreme Court Justice Antonin Scalia has died at the age of 79

Scalia died in his sleep during a visit to Texas

(CNN) —  

U.S. Supreme Court Justice Antonin Scalia, the 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.

His death set off an immediate debate about whether President Barack Obama should fill the seat in an election year. Obama said Saturday night that he plans to nominate a replacement, but Senate Majority Leader Mitch McConnell said the nomination should wait until the next president comes into office while top Democrat Harry Reid called for the seat to be filled “right away.”

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. He didn’t get up for breakfast on Saturday morning, 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.

RELATED: Antonin Scalia fast facts

The U.S. Marshals Service is helping to arrange for his body to be returned to his home in McLean, Virginia, an official told CNN, not to investigate his death.

There will be no autopsy performed, a source familiar with the case confirmed to CNN. The decision for no autopsy was made both by the family and the Texas Justice of the Peace, the source said.

Marshals were not at the resort in Texas where he died, but were called there after the fact, a law enforcement source told CNN. Mashals help supplement security for traveling justices.

RELATED: Scalia’s death sets up big political battle

Presidio County Judge Cinderela Guevara pronounced Scalia dead over the phone Saturday afternoon, according to the Washington Post. Guevara told the Post she made the determination after being assured by law enforcement at the scene that “there were no signs of foul play.”

Guvara also spoke with Scalia’s private physician in Washington and learned the 79-year-old had several chronic conditions. “He was having health issues,” she told the Post. Based on her conversations, Guevara determined Scalia’s heart stopped beating. “It wasn’t a heart attack,” Guevara told the Post. “He died of natural causes.”

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.”

Obama called Scalia’s son, Eugene, to offer his condolences to the entire Scalia family, Deputy White House Press Secretary Eric Schultz said.

Political fight looming

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 be made even more difficult as the fight over Scalia’s replacement will likely emerge as a dominant theme of a wild presidential election.

Nightcap: How Scalia’s death raises the stakes of 2016’s election | Sign up

Speaking while on a presidential trip to Rancho Mirage, California, Obama vowed to nominate a successor to Scalia, who he called “a towering legal figure.”

“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. “These are responsibilities that I take seriously, as should everyone. They’re bigger than any one party. They are about our democracy. They’re about the institution to which Justice Scalia dedicated his professional life.”

RELATED: Who could President Obama nominate to replace Justice Antonin Scalia?

Earlier Saturday, McConnell, a Kentucky Republican, called for the vacancy to be filled after Obama’s presidency ends.

“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.

But Reid, who represents Nevada, called for the seat to be filled “right away.”

“With so many important issues pending before the Supreme Court, the Senate has a responsibility to fill vacancies as soon as possible,” Reid said in a statement. “It would be unprecedented in recent history for the Supreme Court to go a year with a vacant seat. Failing to fill this vacancy would be a shameful abdication of one of the Senate’s most essential Constitutional responsibilities.”

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.

He was also concerned that some members of the bench might determine that the death penalty is unconstitutional.

RELATED: Political world honors Scalia on Twitter

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.

RELATED: How Justice Scalia transformed court

This term was slated to be every bit as blockbuster as last term. The court is considering a major challenge to public sector unions, a race-conscious admissions plan at the University of Texas, a big abortion case, voting rights, the contraceptive mandate and a challenge to Obama’s immigration actions.

Although in some of the cases Scalia probably indicated to his colleagues in conference which way he was going to vote, those preliminary votes aren’t binding and are now void.

“The entire tenor of this term has now changed,” said Stephen Vladeck, a CNN contributor and a law professor at American University Washington College Law. “The court can try to go ahead, but on cases where they are split 4-4, their only options are to leave the lower court decision intact or to hold the case over until Justice Scalia’s replacement is confirmed.”

If the Supreme Court is equally divided in a case, ruling 4-4, it means the lower court opinion stands and there is no precedent set by the high court.

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.”

RELATED: ‘Jiggery-pokery’: The best lines from Antonin Scalia’s Obamacare dissent

“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.

RELATED: What happens to Supreme Court cases this year?

“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.”

Scalia, a Catholic, regularly attended Red Mass before each term. He and his wife had nine children and more than 30 grandchildren.

His best friend on the bench was Justice Ruth Bader Ginsburg, whom 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.

Political world reacts

Reaction and condolences quickly poured in from politicians and presidential hopefuls. President George H.W. Bush, who was vice president when Scalia was appointed to the court, called him one of Reagan’s “many enduring legacies to the United States.”

RELATED: How Scalia’s death could change America

“Both his admirers and his detractors agreed that Justice Scalia was one of the sharpest constitutional intellects to ever serve on the bench,” Bush said in a statement. “I considered him a personal hero, and Barbara and I were honored to call him a friend. Our heart breaks today for our country, but especially for his wife Maureen and his nine children and extended family. His death is a great loss for us all.”

GOP 2016 front-runner Donald Trump issued his condolences to Scalia’s family in a statement but tweeted that his death was a “massive setback” for conservatives.

“The totally unexpected loss of Supreme Court Justice Antonin Scalia is a massive setback for the Conservative movement and our COUNTRY!” Trump tweeted.

Vermont senator and Democratic presidential candidate Bernie Sanders also tweeted his condolences to Scalia’s family.

Texas Sen. Ted Cruz, who is a member of the Judiciary Committee, echoed McConnell’s call for Obama to hold off on selecting a replacement.

“Justice Scalia was an American hero. We owe it to him, & the Nation, for the Senate to ensure that the next President names his replacement,” Cruz tweeted.

Hillary Clinton said in a statement that she “did not hold Justice Scalia’s views, but he was a dedicated public servant who brought energy and passion to the bench.”

But, she added, “The Republicans in the Senate and on the campaign trail who are calling for Justice Scalia’s seat to remain vacant dishonor our Constitution. The Senate has a constitutional responsibility here that it cannot abdicate for partisan political reasons.”

Former CNN Supreme Court producer Bill Mears researched and wrote much of this obituary prior to Scalia’s death. CNN’s Steve Almasy, Mary Kay Mallonee Stephen Collinson, Jake Tapper, Manu Raju and Emma Lacey-Bordeaux contributed to this report.