A dramatic appellate process appears in the offing. The question is whether Congress can compel testimony from a former aide to District Attorney Alvin Bragg. The riders of the Second United States Appeals Circuit want more time to come up with an answer, so they stayed an order by the district judge, Mary Kay Vyskocil.

It was 12 hours of judicial whiplash, with Judge Vyskocil issuing a blistering ruling telling Mr. Bragg that “no one is above the law,” including himself. She called him an “elected official” not exempt from the “dogfight” of politics while also defending Congress’s constitutional prerogatives to subpoena. 

At the center of it all is an attorney, Mark Pomerantz, who formerly joined Mr. Bragg’s office on a pro bono basis to prosecute President Trump. Mr. Pomerantz quit in frustration when Mr. Bragg showed an initial reluctance to do so, after his predecessor and federal prosecutors both failed to charge Mr. Trump on alleged crimes arising from his business enterprises.

The stay, issued by a rider, Beth Robinson, who was nominated to the circuit after previously having served as an associate justice of the Vermont supreme court, took pains to observe that it “reflects no judgment regarding the merits of the parties’ respective positions.” It merely claims time for a “three-judge panel to consider” Judge Vyskocil’s decision. 

Judge Robinson directed Messrs. Bragg and Pomerantz to file their briefs on Friday, and for Representative Jim Jordan’s attorneys to respond by Saturday. An attorney for Mr. Pomerantz, Ted Wells, opined that “Mr. Pomerantz views the subpoena served on him by Congressman Jordan as an improper attempt to obstruct and impede the pending prosecution of former President Trump by District Attorney Bragg.”

It is likely that no matter who prevails before the Second Circuit, an appeal to the Supreme Court could be in order. The justices would then weigh a question of federalism — whether a congressional subpoena can reach the office of a state prosecutor building a case against a former president. If the logic of Judge Vyskocil’s ruling is upheld, it could be Mr. Bragg who is next called to Capitol Hill for questioning.