A federal judge has agreed to review the Trump administration’s $1.8 billion “anti-weaponization fund” after a group of former federal judges challenged its legitimacy.

The fund was established following Trump’s lawsuit against the Internal Revenue Service over the leak of his tax returns.

Rather than proceeding to trial, Trump administration lawyers and the president’s personal legal team settled by agreeing to create the taxpayer-supported fund.

U.S. District Judge Kathleen Williams in Florida ordered Trump’s lawyers to respond to a motion filed by 35 former federal judges appointed by both Democrat and Republican presidents.

The former judges argued that Trump is effectively both the plaintiff and the defendant, having filed the lawsuit as president while also leading the executive branch overseeing the IRS.

They described the lawsuit as a “fraud on the court” and characterized the case as a form of “collusion” between the president’s lawyers and the federal government, amounting to the “looting” of American taxpayers.

Williams, appointed by former President Barack Obama, had initially granted a dismissal of Trump’s lawsuit following the settlement but said the court is “empowered to investigate serious misconduct.”

A separate judge, U.S. District Judge Leonie Brinkema in Virginia, ordered Trump officials to stop setting up the pool of money to “ensure that no funds are irreversibly disbursed.”

Brinkema, an appointee of former President Bill Clinton, set a June 12 hearing for arguments over whether that order should be extended.

The freeze followed a lawsuit brought by former Justice Department lawyer Andrew Floyd and other plaintiffs, who argued the nearly $2 billion was never approved by Congress and “rewards and incentivizes unlawful behavior and facilitates an astounding abuse of taxpayer funds.”

A Justice Department spokesperson did not respond to a request for comment, though officials said on social media, “We will do everything in our power to make whole those who were persecuted for political purposes.”

The fund has drawn criticism on Capitol Hill, with opponents describing it as a slush fund for Trump supporters claiming to be victims of political persecution.

Legal experts have raised particular alarm over the fund’s lack of oversight and its apparent disconnect from the original claims Trump made in his lawsuit against the IRS.

Adam Zimmerman, a law professor at the University of Southern California, noted that past presidential compensation funds, whether tied to the Holocaust or the BP oil spill, resolved large-scale litigation involving clearly identified victims.

“All those cases involved identifiable injuries, to discrete groups of people, for violations of real laws, under neutrally applicable rules, often brokered in the shadow of a class action litigation or mass litigation,” Zimmerman said.

This fund, he argued, “doesn’t address real legal injuries” and “offers money to an indeterminate group of people, who never threatened or commenced any kind of legal action,” calling it “unlike anything we’ve seen in the history of the republic.”