As President Donald Trump focuses on global trade deals and dispatching troops to aid his immigration crackdown, his lawyers are fighting to erase the hush money criminal conviction that punctuated his reelection campaign last year and made him the first former — and now current — U.S. president found guilty of a crime.

On Wednesday, that fight landed in a federal appeals court in Manhattan, where a three-judge panel heard arguments in Trump’s long-running bid to get the New York case moved from state court to federal court so he can then seek to have it thrown out on presidential immunity grounds.

It’s one way he’s trying to get the historic verdict overturned.

The judges in the 2nd U.S. Circuit Court of Appeals spent more than an hour grilling Trump’s lawyer and the appellate chief for Manhattan district attorney’s office, which prosecuted the case and wants it to remain in state court.

At turns skeptical and receptive to both sides’ arguments on the weighty and seldom-tested legal issues underlying the president’s request, the judges said they would take the matter under advisement and issue a ruling at a later date.

But there was at least one thing all parties agreed on: It is a highly unusual case.

Trump lawyer Jeffrey Wall called the president “a class of one” and Judge Susan L. Carney, noted that it was “anomalous” for a defendant to seek to transfer a case to federal court after it has been decided in state court.

Carney was nominated to the 2nd Circuit by Democratic President Barack Obama. The other judges who heard arguments, Raymond J. Lohier, Jr. and Myrna Pérez were nominated by Obama and Democratic President Joe Biden, respectively.

The Republican president is asking the federal appeals court to intervene after a lower-court judge twice rejected the move. As part of the request, Trump wants the court to seize control of the criminal case and then ultimately decide his appeal of the verdict, which is now pending in a state appellate court.

Trump’s Justice Department — now partly run by his former criminal defense lawyers — backs his bid to move the case to federal court. If he loses, he could go to the U.S. Supreme Court.

“Everything about this cries out for federal court,” Wall argued. Wall, a former acting U.S. solicitor general, argued that Trump’s historic prosecution violated the U.S. Supreme Court’s presidential immunity ruling, which was decided last July, about a month after the hush money verdict. The ruling reined in prosecutions of ex-presidents for official acts and restricted prosecutors from pointing to official acts as evidence that a president’s unofficial actions were illegal.