Trump’s advisers have been laying the groundwork for a legal battle for years, arguing that presidents long enjoyed the power not to spend appropriated funds from Congress and that the Watergate-era Impoundment Control Act of 1974 is unconstitutional.

“Impoundment is simply another word for the president’s Article II authority to implement spending measures enacted by Congress in a responsible manner,” Mark Paoletta, general counsel for the Office of Management and Budget, wrote last September.

Paoletta and Russell Vought, Trump’s nominee to lead the OMB, spent much of the last four years at the Center for Renewing America, a conservative advocacy group that made restoring impoundment powers one of its principal causes.

Once back in office, Trump wasted no time testing that vision. He issued multiple Day One executive orders freezing funds to various programs that he says do not fit his policy goals, then supercharged the effort with the ill-fated blanket freeze memo.

Trump and his opponents agree that the battle is likely to escalate from here.

“This is NOT a rescission of the federal funding freeze,” White House press secretary Karoline Leavitt wrote when the memo was taken back. “It is simply a rescission of the OMB memo. Why? To end any confusion created by the court’s injunction. The President’s EO’s on federal funding remain in full force and effect, and will be rigorously implemented.”

White House officials said reports that the spending pause was over were a “hoax.”

A group of 23 states suing Trump over the freeze made the same point, arguing that its lawsuit should continue because the overriding policy remains in effect. U.S. District Judge Jack McConnell, an Obama appointee who heard arguments in a Rhode Island courthouse, seemed to agree.

“While the piece of paper (memo) may not exist, there is sufficient evidence that the defendants collectively are acting consistent with that directive and therefore their arguments about needing a temporary restraining order for their various legal rights exist,” he said.

If the case or one like it winds its way up to the Supreme Court, Trump’s advisers like their chances.

Paoletta has contributed to multiple lengthy articles making the case for presidential impoundment powers. He wrote that the executive branch enjoyed the privilege for nearly 200 years, with presidents ranging from George Washington and Thomas Jefferson to John F. Kennedy and Lyndon Johnson all impounding funds until Congress outlawed the practice at the height of the Watergate scandal.

“Since the founding, Congress’s power of the purse has been understood to establish a ceiling on executive spending, not a floor,” another Center for Renewing America piece reads, “and certainly not an authority for Congress to compel the president to expend the full amount of an appropriation.”

Of course, the other side of the battle thinks it has the upper hand, too.

Former U.S. Attorney Joyce Vance said Trump does not have the power to impound funds, pointing to the 1974 act and a 1975 Supreme Court decision.

“The Impoundment Control Act, like much of the legislation requiring presidents to follow the law, was passed in reaction to the Nixon presidency,” she wrote on Substack. “It effectively ended a president’s power to impound funds. The year following its passage, the Supreme Court held in Train v. City of New York that even without the act, presidents lack the authority to impound funds. Train reaffirmed the clear grant of the power of the purse to Congress in the Constitution.”

However, some legal scholars, such as University of California, Berkeley professor John Yoo, argue that Train does not really concern the Impoundment Control Act but rather the narrow text of a specific act of Congress and that Trump may have a decent shot of winning in court.

“Trump can interpret the Constitution his own way to say it allows him to keep this discretion that presidents since at least Thomas Jefferson had,” Yoo said. “There’s an open question about this, and Trump is entitled to try to press his powers and to try to go to the Supreme Court.”

Like many executive powers arguments, politicians’ stances on impoundment depend on which party controls the White House. When reports circulated last year that then-President Joe Biden was threatening to withhold military aid to Israel that was approved by Congress, Republicans condemned the move and sought to force Biden to relinquish the threat.

The funding freeze saga has heightened Democratic opposition to Vought’s nomination to lead the OMB, and Democrats boycotted a vote to advance him in the Senate on Thursday, though the measure still passed with Republican support.

Vought remains on track to be confirmed, and the impoundment matter is almost certain to wind its way through the courts as his theory tests the constitutional waters.

Craig Shirley, a presidential historian and Ronald Reagan biographer, said Trump has already won the political argument with his antispending push and predicted he could win in court as well.

“It is time to overturn the impoundment act,” Shirley said. “A president has to be free to operate to help the American taxpayer against a profligate Congress.”