Hunter Biden requested Wednesday to subpoena former President Trump and three senior officials who served in his administration’s Justice Department, seeking evidence that Biden’s criminal prosecution is politically motivated.

Biden, who faces three federal gun charges, is demanding Trump and former Attorney General Bill Barr turn over communications and documents concerning the president’s son or his criminal investigation.

The demands for documents, which must be approved by a judge, also extend to former Deputy Attorney General Richard Donoghue and former acting Attorney General Jeffrey Rosen.

“Mr. Biden seeks specific information from three former DOJ officials and the former President that goes to the heart of his defense that this is, possibly, a vindictive or selective prosecution arising from an unrelenting pressure campaign beginning in the last administration, in violation of Mr. Biden’s Fifth Amendment rights under the Constitution,” Biden’s attorneys wrote in court filings.

After a plea deal evaporated in Biden’s case earlier this year, prosecutors in Delaware indicted the president’s son on three gun-related charges in September. 

He is accused of unlawfully possessing a firearm while addicted to a controlled substance and failing to disclose drug use when seeking to buy a weapon. Biden, who has acknowledged his struggles with addiction, pleaded not guilty.

Republicans have long criticized the investigation into Biden, portraying his now-defunct plea agreement as a “sweetheart deal” and lambasting prosecutors for not charging him with additional crimes in their subsequent indictment.

Biden’s subpoena motion extensively references those criticisms, calling out by name House Oversight and Accountability Committee Chair James Comer (R-Ky.) and House Ways and Means Chair Jason Smith (R-Mo.). Biden accused Trump and his congressional allies of mounting a “sustained, almost-nonstop public pressure campaign” for prosecutors to bring charges.

Comer’s committee last week, as part of their impeachment inquiry, subpoenaed Hunter Biden and other members of the president’s family. The GOP investigation into the Bidens has multiple prongs, including claims they were engaged in influence peddling, as well as claims that some money flowed to President Biden himself during his vice presidency. The White House has vigorously denied any wrongdoing.

“It is clear no measure of charges against Mr. Biden will ever be enough to appease Chairmen Comer and Smith and their MAGA allies,” Biden’s attorneys wrote in their motion.

“As anyone can readily tell, it is not just pressure from within the Trump-era Executive Branch that is the problem; it is also incessant, unrelenting outside interference from congressional Republicans and their allies in the prosecutorial process, which is supposed to be independent and free from political interference,” the motion continued. “Undoubtedly, the current political climate has jeopardized that longstanding and fundamental American principle.”