Supreme Court Justice Antonin Scalia testifies before a House Judiciary Commercial and Administrative Law Subcommittee hearing on The Administrative Conference of the United States on Capitol Hill in Washington in this May 20, 2010 file photo.
WASHINGTON - The sudden death of Justice Antonin Scalia, a towering conservative icon on the US Supreme Court, has set off an epic election-year battle over his successor that will shape American life far into the future.
Scalia died of an apparent heart attack at age 79, leaving what had been a conservative-dominated court evenly divided in a year of blockbuster cases - on abortion, affirmative action, immigration and President Barack Obama&39;s health care law.
The news sent shockwaves through the White House race, as Republican and Democratic candidates absorbed the implications of the surprise, potentially course-altering opening on the court.
"I think last night with the passing of Justice Scalia, we are reminded of how important this election is, how high the stakes are and why we must win," Senator Marco Rubio, in a bitter fight for the Republican nomination, told "Fox News Sunday."
Firing the first shot in the succession battle hours after Scalia&39;s death, Obama said he would exercise his "constitutional responsibilities" and name a successor.
Leading Republicans - including all six conservative White House contenders - threatened to block any nomination Obama puts forth, arguing that it should be left to the next president to fill Scalia&39;s vacant seat.
Republicans contended that no president in recent history has nominated a Supreme Court Justice in his final year in office.
But Justice Anthony Kennedy, nominated by Ronald Reagan, was confirmed in 1988, an election year.
Obama called on the Senate to give his nominee a "fair hearing and a timely vote."
The president nominates Supreme Court candidates, but Senate approval is required for them to take up the lifetime post, a long tenure that allows members of the court to be free from the political pressures of running for office.
Obama ordered flags to fly at half-staff across the United States to mark Scalia&39;s passing, praising him as "one of the towering legal figures of our time."
Scalia died at a private ranch in the Big Bend area of West Texas during a hunting trip. Presidio County Judge Cinderela Guevara told WFAA television the cause of death was a heart attack.
Appointed to the Supreme Court by Reagan in 1986, Scalia championed originalism, the legal theory that the meaning of the Constitution should be interpreted as fixed at the time it was ratified, in 1788.
According to this view, there is no doubt as to the validity of the death penalty and the right to bear arms.
A devout Catholic who had nine children, Scalia derided abortion and same-sex marriage as new rights that would have been unfathomable to the writers of the Constitution.
Brilliant, witty and scathing in his opinions, he was known as much for his slashing dissents as his majority opinions.
Scalia "was a bad boy on the bench who certainly never wrote a bad sentence," biographer Joan Biskupic told CNN.
To the surprise of some, the portly, affable Scalia was able to separate his legal opinions from his personal relations, celebrating New Year&39;s each year with liberal Justice Ruth Bader Ginsburg and taking the newest justice Elena Kagan skeet shooting.
"He was a jurist of captivating brilliance and wit, with a rare talent to make even the most sober judge laugh," Ginsburg said in remembering her "treasured friend."
And, in a little known anecdote, former Obama senior advisor David Axelrod revealed that Scalia had once rooted for Kagan&39;s nomination.
"I have no illusions that your man will nominate someone who shares my orientation, but I hope he sends us someone smart," Axelrod in a CNN blog post quoted Scalia as telling him during the 2009 White House Correspondents&39; Dinner.
"Let me put a finer point on it. I hope he sends us Elena Kagan."
Kagan was eventually confirmed to the high court, in 2010, and she and Scalia became good friends despite their ideological differences.
Court&39;s future in play
His death&39;s impact on the court will be immediate, even though the succession struggle will take time to play out.
With a 5-4 conservative majority, the court had recently stalled key efforts by Obama&39;s administration on climate change and immigration.
Now, with the court split evenly 4-4, lower court rulings will be upheld in cases that end with a tied decision, thereby blunting the conservatives&39; hold.
This term is stacked high with hot button issues, including the first abortion case since 2007, Obama&39;s sweeping health care reform and whether the president can protect certain immigrants from deportation.
&39;Delay, delay, delay&39;
Republican leaders immediately took up the cry against an Obama nomination to the court, setting the stage for a bruising election year fight.
"Therefore, this vacancy should not be filled until we have a new president," Senate Republican Majority Leader Mitch McConnell said.
His Democratic counterpart Harry Reid said postponing a nomination would be a "shameful abdication" of the Senate&39;s constitutional duties.
Democratic White House hopeful Hillary Clinton said Republicans calling for a delay "dishonor our Constitution."
During a debate Saturday, all six Republican presidential contenders bowed their heads in silence to honor the late justice -- and united to oppose Obama nominating his successor.
Republican frontrunner Donald Trump said it was up to Senate Republicans to "delay, delay, delay" any nomination sought by Obama.