The death of Antonin Scalia could set off a U.S. Supreme Court realignment that reverses decisions touching major facets of American life including gun control, campaign finance reform, and consumer protections. A newly remade 5-4 majority might even consider outlawing the death penalty.

Those stakes help explain why Senate Republicans are vowing to block President Barack Obama from naming a successor to Scalia during the last year of Obama’s presidency. The clash sets up what promises to be an epic battle over the court’s future.

Because Scalia was the anchor of the court’s conservative wing, even a moderate successor would tilt the balance on a court prone to dividing 5-4 on the country’s most contentious legal issues.

“I think it’s going to be really, really bad for conservatives,” said Brian Fitzpatrick, a former Scalia law clerk who now teaches at Vanderbilt University Law School in Nashville, Tennessee. With a Democratic-appointed successor, “you can’t get the same five votes that you used to get.”

Democrats have stockpiled legal grievances since 2006, when Justice Samuel Alito replaced the retiring Sandra Day O’Connor. Since then, Alito has joined Chief Justice John Roberts and Justices Scalia, Clarence Thomas and Anthony Kennedy to roll back longstanding civil rights protections, open the way for new campaign spending, declare that the Constitution protects individual gun rights, and shield businesses from lawsuits.

A Democratic choice to replace Scalia would let the court’s liberal wing overturn those decisions, or at least scale back their significance, if cases raising the issues reach the justices.

Campaign Spending

White House spokesman Eric Schultz said Monday that Obama would look for an appointee who saw the work of the court as not “just about legal theories” but “protecting people’s freedoms.” While Obama expects his pick to adhere to precedent and have a commitment to impartiality, Schultz said, the nominee should also consider “how laws affect people’s daily lives.”

QuickTake U.S. Campaign Finance

The most likely decision to be targeted for reconsideration if a Democratic president chooses Scalia’s replacement may be the 2010 Citizens United ruling, which let corporations spend unlimited sums on political causes. Critics including Obama blame that ruling for ushering in a new wave of campaign spending. Democratic presidential candidates Hillary Clinton and Bernie Sanders have said they would insist their Supreme Court nominees oppose Citizens United.

The court’s four Democratic appointees -- Justices Ruth Bader Ginsburg, Stephen Breyer, Sonia Sotomayor and Elena Kagan -- said in 2012 they would like to reconsider the ruling.

“The liberal justices have made no secret of their desire to overturn Citizens United as soon as possible,” said Jeffrey Rosen, president of the National Constitution Center in Philadelphia.

That group of justices has been similarly steadfast in opposing 5-4 rulings that limited class-action lawsuits and let companies channel disputes with consumers and employees into arbitration instead of the courtroom.

The four Democratic nominees have also lined up against decisions expanding religious rights, most notably the 2014 ruling that said companies can refuse on religious grounds to offer birth-control coverage to their workers. The foursome was in dissent as well in 2013, when the court struck down a core part of the Voting Rights Act, the landmark 1965 law that opened the polls to millions of southern blacks.

Liberal Quandary

One issue for the court’s liberals would be whether they would directly overturn those decisions or simply limit them to the particular circumstances of the case. The group has spent much of the last decade accusing the conservative wing of being too quick to topple old decisions, and now the shoe may be on the other foot.

“That might give them some pause,” Rosen said. “It’s just a tremendously interesting question whether, if the liberals had a solid majority, they would immediately move to overturn all the 5-4 decisions in which they were in the minority.”

One area where the justices might hold off is the Second Amendment, Fitzpatrick said. The court’s 2008 Heller v. District of Columbia decision, written by Scalia, conferred individual gun rights but has had limited practical consequences.

The court in that case invalidated a handgun ban in the nation’s capital and later overturned a similar Chicago law. The justices otherwise have left states and local governments free to enforce less sweeping restrictions.

‘Lot of Play’

“There’s a lot of play in the joints there,” Fitzpatrick said. “Even though I don’t think the Supreme Court is going to overturn Heller, there were a lot of open questions about how many regulations the government could place on individual gun owners.”

The court, he said, could leave Heller in place and “just say all these new regulations are justified.”

Republican Senator Ted Cruz, running to succeed Obama, said on Sunday the court was “one justice away from the Second Amendment being written out.” He called the 2016 election a referendum on the Supreme Court.

Schultz said Monday that voters already had a chance to weigh in on appointments to the court by re-electing Obama in 2012. The White House expects Senate Republicans to fulfill their “constitutional responsibilities”by considering a nominee, he said, warning of “consequences” if the court is left shorthanded.

"Our expectation is that members of the United States Senate will do their job," Schultz said. "And that includes Republicans."

A reconstituted court also might be bolder on capital punishment. Breyer and Ginsburg have already hinted they would strike down the death penalty. The prospect of having five votes to declare it unconstitutional might be enough to prompt Kagan and Sotomayor to join the cause, Fitzpatrick said.

“I wouldn’t be surprised if the other two liberals would be happy taking that view as well and they just haven’t come out and said it yet,” Fitzpatrick said. “I could see that being something that is not outside the realm of possibility.”