A federal appeals court will weigh arguments Tuesday about Donald Trump‘s claims that his presidency and his 2021 impeachment acquittal should immunize him from prosecution over an alleged attempt to overturn the 2020 election.

A three-judge panel on the U.S. Court of Appeals for the District of Columbia Circuit will hear oral arguments about Trump’s claim that he has immunity from prosecution. Trump, who is seeking to remain the top contender in the Republican primary as the Iowa caucuses approach next week, is taking time off the campaign trail to attend the oral arguments on Tuesday in the nation’s capital.

The appearance marks Trump’s first return to the E. Barrett Prettyman U.S. Courthouse since he pleaded not guilty to the four-count indictment in August. It also stands as a show of force for his public polling dominance over the GOP field, as Trump has consistently avoided orthodox campaigning events since his arrests, favoring the courtrooms as his 2024 backdrop.

On the eve of the appeals court hearing, Trump said Monday he would indict President Joe Biden if the court doesn’t rule his way.

“If I don’t get Immunity, then Crooked Joe Biden doesn’t get Immunity, and with the Border Invasion and Afghanistan Surrender, alone, not to mention the Millions of dollars that went into his ‘pockets’ with money from foreign countries, Joe would be ripe for Indictment,” Trump wrote on Truth Social.