Hunter Biden’s lawyer, Abbe Lowell, told U.S. Magistrate Judge Christopher Burke on Tuesday that he will file a motion to dismiss the gun case against his client, because he believes that the July sweetheart plea agreement remains in effect and that the gun statute is unconstitutional.

Burke told Hunter Biden on Tuesday the motion had to be filed by November 3.

The president’s son is charged with one count of false statement in the purchase of a firearm, one count of possession of a firearm by a person who is an unlawful user of or addicted to a controlled substance, and one count of false statement related to information required to be kept by a federal firearms licensed dealer.

Hunter Biden’s sweetheart plea deal with Special Counsel David Weiss collapsed after U.S. District Judge Maryellen Noreika questioned if the plea deal covered future potential charges of the Justice Department’s ongoing investigation. The prosecution said the deal did not include any alleged Foreign Agents Registration Act (FARA) violations.

Weiss and Hunter Biden’s disagreement on the plea deal’s scope caused Weiss to withdraw the agreement and later charge Hunter Biden with three gun violations. Weiss could still bring potential tax charges against the president’s son.

Hunter Biden’s lawyers wrote in a court filing in August that Weiss decided to “renege on the previously agreed-upon plea agreement,” but that the diversion agreement, providing Hunter Biden broad further immunity, is still in effect and binding. The diversion agreement allowed Hunter Biden to plead guilty to misdemeanor tax violations while essentially wiping a felony gun violation from his record.

Lowell’s announcement of his plan to file a motion to dismiss the case came as his client appeared in court on Tuesday, when Hunter Biden pleaded not guilty to the gun charges. Hunter Biden gave “a sense of nervous energy, a nervous smile. A sense of real apprehension as we head into the proceeding,” CBS correspondent Catherine Herridge reported.

The president’s son left the federal courthouse after Judge Burke released him on several conditions. Those conditions appear to be the same as those of the July plea deal, including that he does not possess a gun, use alcohol, or ingest controlled substances.

Follow Wendell Husebø on Twitter @WendellHusebø. He is the author of Politics of Slave Morality.