The United States Supreme Court - and the array of contentious social issues that it decides - has now become a major focus of the 2016 election, and is almost certain to remain that way for the rest of the year.
The unexpected death yesterday of Justice Antonin Scalia, regarded as the dominant figure of the court's conservative majority, has left it deeply divided along ideological lines, much as the country is.
With a year left to go in President Obama's term, it is likely to be left to his successor to appoint a replacement, who would determine whether the court leans left or right.
Shortly after the announcement of Scalia's death, Senate Majority Leader Mitch McConnell, a Kentucky Republican, issued a statement saying that the Senate should not confirm a replacement until after the election. Obama plans to send a nominee to the Senate, but it is unlikely any could get through, especially given the fact that two senators are among those vying for the GOP nomination.
"The American people should have a voice in the selection of their next Supreme Court justice," McConnell said.
Senate Minority Leader Harry M. Reid, a Democrat from Nevada, immediately rejected that position, saying "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".
That elevates the makeup of the court to a front-line issue in the presidential race. It also appears certain to become a central focus in Senate races across the country, as that chamber has the power to confirm whomever the next chief executive would choose.
The last confirmation in the eighth year of a presidency was Justice Anthony Kennedy, whose 97-to-0 Senate confirmation in February 1988 came after two failed nomination efforts by President Ronald Reagan in the face of a Democratic-controlled chamber. Kennedy is now a prime villain among conservative activists, who view his rulings on abortion and gay rights with the high court's liberal bloc as an example of GOP leaders choosing political expediency over ideological rigidity.
The only other attempt to fill a vacancy during a presidential election year came in 1968, when President Lyndon B. Johnson tried to elevate Justice Abe Fortas to chief justice. The Senate blocked Fortas and the other nomination, to fill Fortas' spot as associate justice, was withdrawn during the final months of Johnson's presidency.
Under normal circumstances, the nomination of a justice takes about 75 to 90 days, the first 60 or so involving a thorough vetting process by the Senate Judiciary Committee. But by that point, mid-May, the so-called Thurmond Rule could kick in. (The rule is named after the late Senator Strom Thurmond, R-South Carolina, who during his tenure as Judiciary chairman declared that he would not take up new judicial nominations within a few months of a presidential election.)
The American people should have a voice in the selection of their next Supreme Court justice.
The candidates are certain to be pressed - constantly - to describe the qualifications they will look for in a nominee, as well as the litmus-test questions that would determine their choices.
Republicans will pledge to appoint strict constructionists who will follow the letter of the Constitution, and will also be under pressure to pledge that their choices would roll back court decisions that upheld the Affordable Care Act and legalised gay marriage. Democrats will press for nominees who would overturn court decisions such as the one that opened up the floodgates for unregulated money in elections, and who would hold the line against efforts to narrow voting rights protections and access to abortion.
Even with a conservative majority, the court has been a target on the right. Shortly after it ruled last July in favour of same-sex marriage, Senator Ted Cruz of Texas, now a Republican presidential contender, proposed a constitutional amendment that would impose term limits on Supreme Court justices.
"This past term, the court crossed a line and continued its long descent into lawlessness to a level that I believe demands action," Cruz said.
In an era when the legislative and executive branches have been at loggerheads, it has increasingly fallen to the court to decide the direction of major political issues and even the social fabric of the nation.
During Obama's years in office, that has included decisions on the fate of the Affordable Care Act, same-sex marriage, environmental issues, immigration policy, voting rights and redistricting, religious freedom, racial discrimination, reproductive rights and the extent of presidential powers.
Usually, discussions of Supreme Court nominations during presidential elections are theoretical ones. Before Scalia's death, the question of Supreme Court appointments had fallen into that category, given that four of the justices were in or approaching their 80s.
Democratic frontrunner Hillary Clinton caused a recent stir when an Iowa voter asked if she might consider appointing Obama.
"Wow, what a great idea. Nobody has ever suggested that to me. Wow. I love that. Wow. He may have a few other things to do, but I tell you, that's a great idea," she replied.
On the Republican side, leading candidate Donald Trump caused consternation in December, when he criticised Scalia for questioning affirmative action.
After Scalia said that minority students who did not qualify for elite universities might do better at "less advanced schools", Trump said: "I don't like what he said, no, I don't like what he said. ... I'm going, 'Whoa'."
Yesterday, Trump said Scalia was "a remarkable person and a brilliant Supreme Court justice, one of the best of all time".
Even before Scalia's death, the Supreme Court rulings had become a focal point in both presidential nominating contests.
Cruz, running as the most conservative on social issues, frequently cites the nomination of Kennedy and Roberts as huge mistakes by Reagan and former president George W. Bush, vowing to only appoint clearly conservative jurists in the mold of Scalia if he wins the presidency.