In June, federal prosecutors, led by Delaware U.S. Attorney David Weiss, reached a two-part deal with Hunter Biden that would have resulted in his pleading guilty to two tax misdemeanors and his entering a pretrial agreement intended to lead to the withdrawal of a gun charge. Hunter Biden and a prosecutor on Weiss’ team both signed the pretrial agreement, which included language protecting him from future criminal charges.

But after a contentious July hearing, the plea deal appeared to collapse. In August, Attorney General Merrick Garland made Weiss a special counsel, formally broadening his prosecution authority. Weiss, who was originally appointed to his U.S. attorney post by former President Donald Trump, brought the Delaware gun charges in September and also obtained the recent tax indictment accusing Hunter Biden of failing to pay federal income taxes over a three-year period.

Hunter Biden’s lawyers argued Monday that the pretrial agreement both sides signed in July remains binding.

Hunter Biden’s former lawyer Chris Clark — who negotiated the deal with the Justice Department and then left his legal team after its collapse — entered a statement to the court supporting his former client. Clark said that the deal’s unorthodox two-part structure was the Justice Department’s idea. He also said the deal was written to “protect Mr. Biden from being charged for the same conduct by a possible future Trump-led DOJ.”

In addition to shielding him from the gun charges, Hunter Biden’s lawyers contended that the pretrial agreement “would seem to bar” the recently filed tax charges in California as well.

Aside from the somewhat technical arguments about the status of the pretrial agreement, Hunter Biden’s lawyers lodged aggressive constitutional attacks on the nature of the prosecution and the merits of the gun charges. They cited an August decision from the New Orleans-based 5th Circuit Court of Appeals that struck down the federal law banning drug users from possessing guns. That decision is not binding in Delaware, but the federal government has asked the Supreme Court to clarify the law’s constitutionality.

Hunter Biden struggled for years with drug and alcohol addiction, which he chronicled in 2021 memoir. The gun indictment alleges he purchased a gun in 2018, a time when he has written that he regularly used crack cocaine.