Louisiana Republican Sen. Bill Cassidy signed onto an amicus brief calling President Donald Trump’s “weaponization” fund a “dire threat” to Congress and the constitutional order.

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The from Cassidy and Sen. Cory Booker, D-N.J., was filed Wednesday in a case challenging the fund that’s working its way through court in Virginia. Cassidy last month lost out of a runoff in Louisiana amid a Trump-backed primary challenge, and Congress is weighing amendments to a budget reconciliation bill that could ax the “lawfare” fund entirely.

Cassidy’s inclusion on the brief is a window into the broad opposition to the fund from Senate Republicans, who rarely buck Trump due to potential political consequences. It also underscores how Cassidy, who has no more elections to run, could complicate future votes in the Senate.

The brief argues that the court, which halted the fund temporarily in May, should uphold its block. The senators argued that the fund represents the “immediate and dire threat to our constitutional order and the authority of Congress.”

“The existence of the Fund strikes at the core of Congressional authority and our Constitutional order,” the senators said.

The lawmakers say the fund violates the “Spending, Appropriations, and Appointments,” while stepping on Congress’s authority over the federal purse. They argue it could also financially compensate convicted violent rioters who stormed the Capitol on Jan. 6, 2021, trying to disrupt the certification of former President Joe Biden’s electoral victory.

“To deliberately deploy public funds, in violation of the Constitution and the laws of this nation, to compensate these perpetrators is to use the machinery of democratic government to subsidize an attack on that government’s most fundamental processes,” the brief reads.

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The fund originated as part of a settlement of Trump’s $10 billion lawsuit against the Internal Revenue Service for the leak of his tax returns. In exchange for dropping that case, the Justice Department set up a $1.8 billion legal relief fund to compensate victims of what the administration calls “lawfare.”

Acting Attorney General Todd Blanche testified Tuesday before Congress that the Justice Department has permanently abandoned the weaponization fund and would not pursue it regardless of the outcome in court. Trump and his family, however, maintain protected from audit and other tax enforcement actions in connection with tax returns filed before last month’s out-of-court settlement of his lawsuit, as per the original settlement that created the fund.

And Trump, speaking with reporters Wednesday in the Oval Office, said he didn’t know if it’s “dead” or “on hold,” saying he’d have to “ask the lawyers.”

Critics have argued DOJ’s initial statement saying it would not proceed with the fund did not make clear whether the department had dropped any plans for the fund, and are eyeing a more permanent solution.

“The Court should maintain an injunction against the implementation of the Anti-Weaponization Fund and ultimately render judgment for the Plaintiffs in this matter,” the senators said in the brief.

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