Richard Wolf

USA TODAY

WASHINGTON — The Supreme Court that begins its 2016 term Monday stands at the threshold of an ideological transformation unmatched in nearly a half century, one that eventually could put in play legal precedents ranging from Roe v. Wade to Citizens United.

Not since 1968 has a presidential election carried such momentous implications for the nation's highest court, now divided down the middle following the death of conservative icon Antonin Scalia. That election gave Richard Nixon four appointments to the court and installed a conservative majority that endured, however haltingly, until this year.

A victory by Hillary Clinton not only would break the glass ceiling at the White House but shake the foundations of the court''s marble palace, leading to its first liberal majority since the Vietnam era. Donald Trump's election, on the other hand, would continue and perhaps even advance conservative control for decades to come.

While the change in personnel could happen fast — beyond Scalia's seat, three other justices are between 78 and 83 years of age — the ideological shifts may take years to play out, particularly in areas of the law that have been relatively stable for decades. But Supreme Court experts predict repercussions from the 2016 election will grow in significance over time.

Democrats stand the most to gain in the short run. The confirmation of federal appeals court judge Merrick Garland, President Obama's nominee for Scalia's seat, or someone else of Clinton's choosing would imperil conservative precedents in areas ranging from campaign finance and voting rights to religious liberty and executive power. Should Justice Anthony Kennedy leave the bench during Clinton's presidency, liberals could gain a sixth seat.

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Under Trump, conservatives cannot improve upon Scalia, except perhaps in the area of criminal defendants' rights, where he often sided with the court's liberal wing. But should Trump get to replace Justices Ruth Bader Ginsburg or Stephen Breyer, he could solidify the conservative court GOP presidents have sought, with mixed results, for decades. That could reverse liberal victories in areas such as abortion rights and affirmative action.

"You don't get many opportunities like this," says Burt Neuborne, professor of civil liberties at New York University School of Law, who is writing a book about Supreme Court upheavals. Since the Civil War, liberals have controlled the court for just 35 years, he says, adding: "This will be a unique and precious moment, if it happens."

'Rare moments' in history

The last two presidents who made such a difference on the court were Nixon and Franklin Roosevelt three decades earlier. FDR's eight nominees and Nixon's four flipped the court majority from conservative to liberal and back again. By the time Clarence Thomas replaced Thurgood Marshall in 1991, eight justices were Republican nominees, though three voted more often with the liberal bloc.

Those were "rare moments in American history where the ideology of the court changed," says Erwin Chemerinsky, founding dean of the University of California-Irvine School of Law. Nixon, he notes, "dramatically changed the direction of constitutional law."

Bill Clinton's nominations of Ruth Bader Ginsburg and Stephen Breyer, followed 16 years later by President Obama's nominations of Sonia Sotomayor and Elena Kagan, now give liberals parity. With Kennedy's help, they have used their increased clout to dominate the court the past two terms, legalizing same-sex marriage and upholding abortion rights, affirmative action policies and Obama's signature achievement, the Affordable Care Act (twice).

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Scalia's empty seat has produced two parlor games in Washington — one on who will fill it and when, the other on which legal precedents will be undone as a result. Garland remains the favorite to win the first contest, either this fall or next year, but Clinton could opt for a younger, perhaps female or minority candidate. Trump has floated a list of solidly conservative options.

Predictions about the direction of a more liberal or conservative court run the gamut. Some liberals fear for Roe v. Wade, which has protected abortion rights since 1973; some conservatives worry about Citizens United v. Federal Election Commission, which has guarded independent political donations by corporations since 2010.

"With such critical issues as voting rights, reproductive choice, executive power, the death penalty and campaign finance reform likely to come before the justices in coming years, many of the court’s landmark precedents — both recent and longstanding — may hang in the balance," says Elizabeth Wydra, president of the liberal Constitutional Accountability Center.

Most court-watchers believe major changes in the law would not happen quickly. They note that under Chief Justice John Roberts, the court generally has moved incrementally before striking down statutes or reversing its own rulings. Nixon's court, under Chief Justice Warren Burger, moved slowly in areas ranging from business regulation to defendants' rights.

“No one in ’68 saw abortion coming," says David Strauss, professor at the University of Chicago Law School, who has argued 18 cases before the court. "Affirmative action was really not on the radar screen. … Gun rights were nowhere near the radar screen.”

Seven potential pivots

Still, several areas of the law likely would be altered over time by a new, nine-member court:

• Abortion. A liberal court could continue to crack down on laws passed by Republican state legislatures that restrict women's rights, while a conservative court could uphold those laws. Even if conservatives prevail, however, "I don't see the court overturning Roe v Wade," says Curt Levey, legal affairs fellow at the conservative interest group FreedomWorks.

• Affirmative Action. The court's 5-3 ruling in June upholding the use of racial preferences at the University of Texas-Austin indicates that liberals have won that battle with Kennedy's support. But a more conservative court could upend things, perhaps using challenges against Harvard and the University of North Carolina now pending in lower courts. “It invites a more fundamental challenge,” says appellate lawyer William Consovoy, co-director of the Supreme Court clinic at George Mason University School of Law.

• Death Penalty. Breyer's leading role in opposing the death penalty has brought the court closer to abolition than perhaps any time since it was reinstated in 1976. Adding one or more liberal justices could seal its fate. “I think the writing is on the wall,” says Steven Shapiro, legal director of the American Civil Liberties Union. Actions by state legislatures and lower courts, he says, make it "less and less defensible." On the court's fall docket are two capital cases involving racial bias and intellectual disability.

• Election Law. A more liberal court might not overturn Citizens United, at least not immediately, because it's loath to upset precedents after a personnel change. "That's understood as a recipe to undercut the legitimacy of the court," says appellate lawyer Paul Smith, who's argued 19 cases there. He says it's more likely to tackle voting rights restrictions such as photo ID laws, upheld in an Indiana case in 2008. The court has two redistricting cases on its fall docket involving allegations of racial gerrymandering in North Carolina and Virginia.

• Executive Power. The court has made things difficult for the Obama administration on environmental regulation, health care and immigration by limiting the power of executive agencies. A liberal court could defer more to the administration. “Once you set that precedent and the courts say that’s fine … you’ll see presidents from both parties abusing that power," warns Texas Attorney General Ken Paxton. Obama's stalled plan to protect millions of undocumented immigrants from deportation and his effort to crack down on power plant pollution could reach the court after he leaves office.

• Guns. Scalia's 2008 decision in District of Columbia v. Heller gave citizens the right to keep guns at home for self-defense but acknowledged that the right is not without limits, so little change is likely. "The court seems to have fashioned the kind of compromise that most people are not severely unhappy with," says Daniel Ortiz, who directs the Supreme Court litigation clinic at the University of Virginia School of Law.

• Religion. The Roberts Court's defense of religious liberty in a number of recent cases could be at risk if liberals gain sway. That could lead to a stricter dividing line between church and state. Kristen Waggoner, senior counsel at the conservative legal group Alliance Defending Freedom, fears that "Americans will no longer have the right to live consistent with their faith without punishment from the government." On this term's docket is a church-state battle over public funding — for a playground.

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