The potential for another Supreme Court vacancy coming open later this year appears to have liberals panicking.

Rumors of Justice Anthony Kennedy's retirement have swirled for months but recently reached a fever pitch inside the Beltway. Shortly after the presidential election in November, the Supreme Court shot down speculation that Kennedy would leave the high court this year. But Republican Sens. Ted Cruz of Texas and Chuck Grassley of Iowa, both Senate Judiciary Committee members, have said that they expect another vacancy this summer.

Elizabeth Wydra, president of the liberal Constitutional Accountability Center, wrote an opinion piece this week urging, "Justice Kennedy, don't abandon your legacy."

"In the Trump era — with a Senate confirmation process now subject to a simple majority vote, thanks to McConnell and Senate Republicans — it is impossible to imagine any stronger or more able steward of Justice Kennedy's legacy than Kennedy himself," Wydra wrote. "Despite all the pressure and pointed rumors of his retirement, he surely realizes this.

"In the years ahead, Kennedy's influence over the nation's future will be more compelling than ever. In short, the Supreme Court is once again the Kennedy Court."

Wydra also wrote that Kennedy "might be more immune to retirement pressure than Trump and his supporters have bargained for," given Kennedy's unique position on the high court. With four conservatives and four liberals on the court, Kennedy often casts the deciding vote.

There are reasons to doubt the amplification of rumors about Kennedy's retirement. Roger Stone, a political operative who has advised President Trump, told prolific conspiracy theorist Alex Jones this month that Stone could report "authoritatively" that "the president has been informed of the coming resignation of Supreme Court Justice Anthony Kennedy."

Stone said the "frontrunner" to replace Kennedy was "clearly Neil Hartigan from the Western District of Pennsylvania" who Stone said was the runner-up to Justice Neil Gorsuch in the race to replace the late Justice Antonin Scalia. While there's a small chance Stone was referring to the former Democratic Illinois Attorney General Neil Hartigan, it's more likely he messed up the name of Judge Thomas Hardiman, a 3rd Circuit Court of Appeals judge from Pennsylvania who appeared on Trump's Supreme Court short lists.

Ultimately, Kennedy is the only unimpeachable source on the timing and manner of his departure from the Supreme Court. If Kennedy decides how to leave the high court in the same fashion he rules on controversies, he will continue to keep court-watchers guessing.

But the calculus for liberals worried about another Supreme Court vacancy does not appear to have changed. While Missouri Sen. Claire McCaskill opposed Gorsuch's Supreme Court confirmation, she outlined how Senate Democrats view future Supreme Court vacancies in comments to donors at a private fundraiser in March. In audio obtained by the Washington Examiner, the senator, who is up for re-election in 2018, sounded the alarm for liberals about the next vacancy.

"God forbid, Ruth Bader Ginsburg dies, or [Anthony] Kennedy retires or [Stephen] Breyer has a stroke or is no longer able to serve. Then we're not talking about Scalia for Scalia, which is what Gorsuch is, we're talking about Scalia for somebody on the court who shares our values," McCaskill said at the private fundraiser. "And then all of a sudden the things I fought for with scars on my back to show for it in this state are in jeopardy."

Now that the Senate has lowered the threshold for confirming a Supreme Court justice to 51 votes, liberals such as McCaskill look poised to oppose Trump's lower court nominees at every turn. The Trump administration has already selected three individuals — Judge Amul Thapar, Michigan Supreme Court Justice Joan Larsen and Minnesota Supreme Court Justice David Stras — from his Supreme Court short lists for federal appeals court positions, and liberals did not wait long to mount opposition.

"Lower court nominees today can become Supreme Court nominees tomorrow," Wydra said.