The Supreme Court’s grant of a filing extension to the Fulton County district attorney, Fani Willis, underscores that her sprawling racketeering case against President Trump and 18 others faces no shortage of headwinds  — some of her own making, others gusting from above.

The high court delayed by one month, until September 30, the due date for Ms. Willis to respond to a petition from one of her defendants, a former Trump White House chief of staff, Mark Meadows. That request, directed to the high court, argues that in light of the justices’ landmark immunity ruling and the office he once held, he ought to be tried not at Fulton County, but in federal court. 

Mr. Meadows, America’s 29th presidential chief of staff, is charged by Ms. Willis with two crimes connected to efforts to overturn the 2020 election in Georgia. He could have been likewise charged by Special Counsel Jack Smith, but was granted immunity from federal charges in exchange for his testimony. The Peach State allegations, though, were handed up before the Supreme Court’s immunity ruling in Trump v. United States.

That ruling decreed that official presidential acts are presumptively immune. Prosecutors carry a heavy burden to rebut such a presumption, but unofficial acts enjoy no such protection. Some acts that are in the heartland of presidential prerogative are entitled to “absolute” immunity. The responsibility for making these determinations falls to the trial judge. The presiding judge in this case, Scott McAfee, could soon find himself following in Judge Tanya Chutkan’s footsteps in undertaking that investigation.

If Ms. Willis stays on the case — she faces disqualification hearings in December before the Georgia Court of Appeals for her secret romantic affair with her special prosecutor, Nathan Wade — she will likely have to persuade Judge McAfee that her indictment is viable in the wake of Trump. Her office could argue that the 45th president’s interactions with, say, Georgia’s secretary of state, Bradley Raffensperger, were not official acts. 

First, though, Ms. Willis has to contend with Mr. Meadows. Although the North Carolinian has served a president rather than served as one, he nevertheless contends that Trump bears on his prosecution. He argues to the Nine that he is entitled to have his case removed to federal court because the “threat posed by prosecutions against federal officers for actions relating to their federal functions does not evaporate once they leave federal office.”

The former aide-de-camp to the 45th president has been trying to escape Fulton County, a majority-minority and Democratic district centered at downtown Atlanta, where a jury may not be sympathetic to an arch-conservative who represented a rural, overwhelmingly white congressional district. Mr. Meadows’s request was denied by both Judge McAfee and the United States Court of Appeals for the 11th Circuit, which prompted his petition for certiorari to the Supreme Court. 

Now, Mr. Meadows writes the justices that “it is hard to imagine a case in which the need for a federal forum is more pressing than one that requires resolving novel questions about the duties and powers of one of the most important federal offices in the nation.”

Ms. Willis has sought to keep Mr. Meadows in state court at every turn. She maintains that his efforts to reverse the results of the last presidential election were not connected to his duties as chief of staff. State prosecutors prefer to try their cases in state courts, where they are more familiar with the jury pools and procedural rules. Federal juries are drawn from larger geographic areas, and are usually more politically and racially diverse.

It could be a sign of the strength of Mr. Meadows’s arguments that Ms. Willis requested a month’s delay to address them. One Supreme Court justice, Antonin Scalia, in 1988 worried over “weakening the Presidency by reducing the zeal of his staff,” who “typically have no political base of support.” Now it is one such assistant, Mr. Meadows who claims that the law of immunities with respect to staff is “underdeveloped.”

Mr. Meadows has hired one of this era’s most accomplished Supreme Court advocates, Paul Clement, to plead his case. If the Nine choose to hear it, Ms. Willis could have to juggle her efforts to keep the former chief of staff in state court with her push to ward off her own disqualification. Trump argues that Ms. Willis’s relationship with Mr. Wade, and the trips they took together while he was on her office’s payroll, amount to a conflict of interest. 

Trump et al. also contend that her rhetoric accusing her opponents of “playing the race card” is tantamount to poisoning the jury pool. The former president, possibly monitoring Mr. Meadows’s struggles, has not sought to move his own case to federal court. If the erstwhile chief of staff wins before the Supreme Court, though, Trump could soon follow in his deputy’s footsteps.