WASHINGTON (AP) — The Supreme Court returns to the bench one last time Wednesday with two cases left to decide and then a summer break from the news — unless, that is, a justice chooses that moment to announce his retirement.

It's happened before, but not since 1987 and there are no outward signs that anyone is planning to leave.

Before a justice even would have the chance to stun the courtroom, however, the court has to resolve two cases, including an important challenge to the financial health of labor unions that represent government workers.

The justices are considering whether to invalidate state laws that require public employees to pay fees to the unions that represent them in collective bargaining, even if the workers don't want to be union members.

Conservative groups have tried for years to get the court to rule that the laws violate employees' free-speech rights by compelling them to pay money to the unions. The justices came close to deciding the issue in 2016, but Justice Antonin Scalia's death produced a 4-4 tie.

Now, with Justice Neil Gorsuch in Scalia's old seat, anti-union groups are trying again.

The other case involves Florida's claim that Georgia uses too much water from the rivers that flow into the Florida Panhandle and the Gulf of Mexico.

If there is a retirement, Justice Anthony Kennedy, who will soon turn 82, would be the most likely candidate. The other justices around his age are part of the court's liberal wing and are not expected to leave voluntarily while President Donald Trump holds office.

By contrast, Kennedy is a Republican appointee of President Ronald Reagan and votes often with the court's other conservatives, though he joins the liberals on gay rights and other social issues. Like all his colleagues, Kennedy has hired law clerks for next year.

Justice Clarence Thomas just turned 70 and visited the White House for what the court described as a social call. Still, his lunch with Vice President Mike Pence and Oval Office visit with Trump — photos of which Thomas' wife posted on social media — sparked some speculation that Thomas is planning to step down.

Kennedy's retirement would give Trump the chance to move the court further to the right. If it's Thomas who leaves, the ideological balance would be unlikely to shift since he's already the most conservative justice.

One reason the speculation may be nothing more than that is because it's later than ideal to announce a retirement and get a justice confirmed by the start of the new term in October.

Kennedy would know. The last time a justice's retirement was announced in court was in June 1987, when Chief Justice William Rehnquist informed a shocked courtroom that Justice Lewis Powell was retiring.

Nearly eight months elapsed before Powell's successor was confirmed. The Senate defeated President Ronald Reagan's first choice, Robert Bork, and his second choice, Douglas Ginsburg, withdrew from consideration. Kennedy was Reagan's next pick and he joined the court in February 1988.