President Donald Trump can’t directly fire Bob Mueller, the man overseeing the investigation into his campaign’s ties with Russia. (Everyone except the president seems to know that.) So if Trump wants to rid himself of the probe he calls a “witch hunt,” he needs to find someone who can.

The only person with the power, right now, to fire Mueller is Deputy Attorney General Rod Rosenstein. And he’s said he won’t pink-slip the special counsel without “good cause,” as federal regulation requires. If Rosenstein refuses and Trump fires him, then the assignment could fall next in line at the Justice Department is Solicitor General Noel Francisco.

Francisco hasn’t addressed whether he’d fire Mueller, but he’s a Republican Trump appointee who’s already accused the FBI of overreaching. He’s also taken what experts called a “bizzare” position in a case against the SEC that the Supreme Court will hear on Monday. The decision could ultimately affect his — and Trump’s — ability to fire Mueller by watering down the “good cause” standard.

The case, Lucia v. SEC, considers how certain judges who preside over SEC regulation are appointed. But seemingly out of left field, Francisco asked the Supreme Court to expand the scope of the case and consider if the law that requires these judges only be removed “for cause” is constitutional. Anyone with the power to fire Mueller would be held to the same standard.

Francisco later not only asked the Supreme Court to dilute that regulation but also argued that Congress doesn’t have the power to limit the president’s, or one of his appointees’, ability to fire officers, like Mueller.

“If the solicitor general gets this judicial ruling that ‘for cause’ really means any reason related to job performance, then that gives some support for a Rosenstein successor to discharge Mueller,” said Harold Krent, a professor at the Chicago-Kent College of Law, who filed an amicus brief in the case.

To avoid an unconstitutional limitation of the president’s power, Francisco wants the Supreme Court to lower the “for cause” standard to include virtually any reason to fire officers, according to experts. “The president’s constitutional responsibility to faithfully execute the laws requires adequate authority to remove subordinate officers,” Francisco titled one section on his brief to the high court. By extension, that includes the special counsel.

“When I try to figure out why anyone would file a brief as bizarre as the one he [Francisco] filed in this case, that’s what I come up with."

It’s natural for Francisco to ask the Supreme Court to clarify an issue when the lower courts are split, but legal experts called his argument “very unusual,” and even potentially “sinister.” They worry an analogous decision would give support to Rosenstein’s successor — who’s almost certainly Francisco himself — or Trump to fire the special counsel.

“When I try to figure out why anyone would file a brief as bizarre as the one he [Francisco] filed in this case, that’s what I come up with,” added Richard Pierce, a professor at George Washington University’s school of law, who also filed an amicus brief. “It’s a very strange position to take, particularly for a Republican solicitor general.”

Francisco originally contested the challenge to the SEC but switched sides at the end of November — exactly a month after the first charges dropped in Mueller’s probe. That’s when the situation took a strange turn, according to experts.

Noel J. Francisco is sworn-in to testify before the United States Senate Committee on the Judiciary on his nomination to be Solicitor General of the US on Capitol Hill in Washington, DC on Wednesday, May 10, 2017. (Ron Sachs/picture-alliance/dpa/AP Images)

Until that point, the court was only asked to rule on how these SEC judges were appointed. But Francisco asked the Supreme Court to consider their removal as well — which no other party in the case had brought up.

The justices didn’t agree to take up that issue. But in a brief later filed to the court, Francisco still argued that point anyway. “All of us were shocked when the solicitor general filed a brief that devoted 17 pages to the argument that the court said not to address,” Pierce said.

The solicitor general could genuinely believe that removing these judges is inherently connected to appointing them and wants the Supreme Court to clarify, as Krent pointed out. The issue has been a headache for those in the world of financial regulation.

But in the less optimistic version, Francisco’s brief expands his and the president’s ability to fire Mueller, although the Supreme Court almost certainly won’t consider that argument on Monday. And even if the justices did, the opinion wouldn’t come down for months, by which time the probe might have concluded.

Although the Senate likely won’t vote to protect Mueller, lawmakers have been considering several proposals to do just that. And some Republicans have brought up similar concerns as the solicitor general. (Lest we forget the Saturday Night Massacre, when the solicitor general, on President Nixon’s orders, did fire the special prosecutor of the Watergate scandal.)

Republican Sen. John Kennedy from Louisiana, for example, recently told Vox he’s “not sure it’s constitutional for us to tell the president who he can fire and can’t fire.”

Without ever mentioning Mueller’s name, Francisco appears to agree.

Taylor Dolven contributed to this report.