President Donald Trump’s lawsuit against the IRS over leaked tax returns was filed for an “improper purpose,” according to a recent decision by U.S. District Judge Kathleen Williams. In her ruling, the judge referred one of Trump’s lawyers for discipline and criticized the $10 billion complaint as an act of self-dealing.

The judge accused Trump of manipulating the court system by suing a federal agency under his control. This action bypassed a requirement that lawsuit parties have opposing interests. It also laid the foundation for a settlement last spring that granted him immunity from tax audits and created a fund to compensate his allies who claimed unjust persecution.

Though the practical effects of the ruling may be limited, particularly after announcements that the $1.776 billion Anti-Weaponization Fund has been abandoned, the ruling delivers a harsh rebuke of the Trump administration. This decision brings to light a politically sensitive issue for Acting Attorney General Todd Blanche as he prepares for his Senate Judiciary Committee confirmation hearing.

The judge noted, “The nature of the suit itself and the conduct of the Parties and counsel from its filing make plain that this was an attempt to use the Court to provide some legitimacy to an agreement to confer immunity to people and entities affiliated with the President and to earmark billions of dollars from American taxpayers to redress grievances not defined in the law.”

Williams further emphasized that the President may have control over the Executive Branch but, as a party in a civil suit, he must adhere to the legal rules applicable to all parties and lawyers in court. The judge stressed the importance of ensuring that courts are only used for the intended purposes outlined by the Constitution.

The judge referenced Blanche’s congressional testimony in June where he stated the anti-weaponization fund was no longer proceeding. Despite no court filings, Blanche seemed confident that he could “speak for, and bind, both sides.” The judge wrote that Blanche’s actions show there was only one party being represented in the case.

Associated Press writers Fatima Hussein and Michelle L. Price contributed to the report.