The Washington rumor mill is churning with speculation about whether Justice Anthony Kennedy will retire at the end of the Supreme Court's term next month.

The rumors seem to pop up annually in recent years. But with Kennedy’s 30 th year on the high court passing in February and the justice nearing 82, the whispers about his future seem to be growing louder.

And congressional Republicans haven’t been shy in vocalizing their hope for a vacancy on the high court before the 2018 midterm elections. Sen. Dean Heller, R-Nev., for example, told an audience in March he believed Kennedy would retire around early summer.

[Opinion: Anthony Kennedy retirement rumors, true or false, just boosted Dean Heller's re-election]

Though Kennedy may remain on the court for another term — he has, after all, hired law clerks for the next term — outside groups are laying the groundwork for a vacancy.

Americans for Prosperity, a conservative group backed by GOP megadonors Charles and David Koch, rolled out a new initiative focused on judicial engagement in January.

The group has been training its activists about the proper role of judges and the importance of the federal judiciary.

“Justice [Neil] Gorsuch was a real win for the rule of law,” said Sarah Field, Americans for Prosperity’s vice president of judicial strategy. “Everything that we’re doing is really in preparation for the possibility of a vacancy, regardless of who that is.”

[Neil Gorsuch thrills conservatives in first year on Supreme Court]

With activists in 36 states, Americans for Prosperity's new focus on the judiciary marks its first foray into judicial engagement.

Concerned Veterans for America, a partner organization to Americans for Prosperity, led efforts last year to support Gorsuch’s confirmation to the Supreme Court with phone banks and direct mail and digital ad campaigns. But after seeing high levels of engagement from its activists on the issue, Americans for Prosperity decided to commit resources to judicial engagement.

“The Supreme Court being filled by judges who respect the rule of law is one of the most important things when it comes to making sure that people's liberties are secure in our American democracy," said Rebecca Coffman, spokeswoman for Americans for Prosperity. "Without that, the rights guaranteed to us by the Constitution are not necessarily protected.”

But it's not just conservative groups who are readying themselves in the event Kennedy retires.

This week, alumni of the White House and Barack Obama and Hillary Clinton’s presidential campaigns announced a new group called Demand Justice, which seeks to mobilize liberals around issues relating to the federal courts.

Led by former Clinton and Justice Department spokesman Brian Fallon, the group plans to raise $10 million throughout its first year, the New York Times reported.

Fallon told the Times the group has started preparing for an opening on the Supreme Court and has gathered information on the backgrounds of judges included on Trump’s list of potential Supreme Court nominees.

The president released his list first during the 2016 campaign and made his most recent addition in November, bringing the total number of prospective nominees to 25.

“If you think Trump’s attacks on [special counsel Robert] Mueller and the rule of law are bad, just think about the idea of Trump getting the chance this summer to swing the Supreme Court to the far right for years to come,” Fallon tweeted Friday.

If Kennedy were to retire, it would shift the high court to the right, as the 81-year-old justice is typically the swing vote in major cases. In decisions involving abortion and gay marriage, Kennedy has sided with the liberal wing of the bench, and in cases involving campaign finance and the Second Amendment, he's joined the conservative justices.

Driven by rumors of retirement and the impact his departure would have on the court, the New York Times editorial board to wrote an open letter to Kennedy late last month begging him to stay and warning his legacy could be affected if he were to leave and Trump appointed a solid conservative justice to replace him.

“Justice Gorsuch replaced Antonin Scalia, a move that didn’t disrupt the balance of the court. Replacing you with a hard-line conservative, in contrast, would have enormous consequences for the nation’s laws and Constitution for decades to come,” the editorial board wrote. “Just ask Sandra Day O’Connor, your onetime fellow swing justice who left the court in 2006 and now watches helplessly as her replacement, the arch-conservative Samuel Alito Jr., votes to tear down her legacy.

“As Justice O’Connor would tell you, legacy isn’t only what you do when you’re on the court; it’s also the circumstances in which you leave it. To put it bluntly, did you spend a lifetime honoring and upholding the Constitution and the values of civility and decency in American public life only to have your replacement chosen by Donald Trump?”

Despite the preparations being made for another vacancy on the high court, Kennedy hasn’t given any indication publicly he’s preparing to step down.

In addition to hiring law clerks for the term beginning in October, the 81-year-old will teach in Salzburg, Austria, in July as part of the McGeorge School of Law summer program — his 28 th year doing so.

Carrie Severino, chief counsel of the conservative advocacy group Judicial Crisis Network, said there are frequently rumors about a possible Kennedy retirement, particularly as the term begins to wind down. But Severino said that ultimately, the decision to step down from the bench lies only with the justice.

Still, her group is preparing in the event he does retire.

“Our policy is always to be ready,” she said. “You never know when the next vacancy will arrive.”

Severino said that with his public list of Supreme Court contenders, Trump made it easy for conservatives to lay the groundwork for an open seat on the bench.

[Also read: Judicial Crisis Network launches ad campaign applauding Trump and McConnell on judges]

“There have been a few changes, but that is great because it gives us the confidence that we know the people on this list are excellent and have a great track record,” she said.

But Severino said she believes it’s “premature” to assume this Supreme Court term will be Kennedy’s last.