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Attorneys for the Trump administration on Tuesday night filed an emergency request with the Supreme Court to allow it to block billions in foreign aid spending that had been appropriated by Congress. The filing returned the USAID funding fight to the Supreme Court for the second time in six months.

Congress had set aside nearly $12 billion for foreign aid spending for the U.S. Agency for International Development, or USAID, but the money must be obligated before the fiscal year ends on September 30. Trump, upon returning to office in January, quickly issued an executive order on his first day back in the White House, instructing the federal government to stop almost all foreign aid spending. The president said at the time that he was making a push to find “waste, fraud, and abuse” in spending on foreign projects.

The executive order was almost immediately challenged in court, and in February, U.S. District Judge Amir Ali in Washington, D.C., issued an order blocking the administration from further efforts. The judge ruled that the White House was obligated to continue releasing funds to projects that Congress had already approved and ordered the Trump administration to resume payments on billions of dollars in USAID grants.

The Trump administration has been fighting that order almost ever since. The U.S. Court of Appeals for the D.C. Circuit returned to the case this month, deciding 2-1 to vacate the injunction imposed by Ali. Writing for the majority, Judge Karen L. Henderson, an appointee of George H.W. Bush, said that the plaintiffs in the case — the foreign aid groups seeking to restore their grant funding — did not have adequate grounds to sue the administration. Henderson wrote that the groups lacked a proper “cause of action” under the law known as the doctrine of impoundment.

That decision from the appeals court was a major victory for Trump, but it had not yet formally issued a mandate to enforce the decision. As a result, the earlier order from Judge Ali and the schedule for payments that he issued technically remain in place. The Trump administration is now racing to get a decision from the Supreme Court before it is forced to release the entire $12 billion before the fiscal year ends at the end of September.

The brief filed by U.S. Solicitor General D. John Sauer with the Supreme Court on Tuesday night makes clear just how urgent the situation has become. Sauer, who filed the emergency request with the Supreme Court on Tuesday, argued that if the justices do not step in, the government will be forced to “rapidly obligate some $12 billion in foreign-aid funds by the end of the fiscal year on September 30.” The Justice Department legal filing also argued that the dispute between Congress and the executive branch should not be settled by federal courts.

“Congress did not upset the delicate interbranch balance by allowing for unlimited, unconstrained private suits,” Sauer wrote in the filing. He added that “any lingering dispute about the proper disposition of funds that the President seeks to rescind shortly before they expire should be left to the political branches, not effectively prejudged by the district court.”

The foreign aid groups and organizations that are the plaintiffs in the case have argued just the opposite. As they see it, the president does not have the right to unilaterally block money from being released from funds that Congress has already appropriated for specific purposes. The plaintiffs, a coalition of foreign aid groups that run projects around the world on USAID funding, point to the Impoundment Control Act, or ICA, and the Administrative Procedure Act as their primary statutory basis for their argument.

ICA is a law originally passed in the 1970s to prevent executive overreach in federal spending. Passed over the veto of President Richard Nixon, it was written in part to help prevent precisely this sort of conflict from arising between the executive and legislative branches. In either case, the plaintiffs are asking the court to effectively intervene on their side in this case to preserve their funding.

Trump has been moving rapidly on foreign aid since taking office in 2017, and the fight over USAID spending is part of that larger effort to both reduce the overall amount of foreign aid spending as well as to assert control over who gets the money. The Supreme Court has already weighed in on a similar dispute over the funding this year in a narrow 5-4 decision, so the case is not without precedent as the fiscal deadline quickly approaches. But with billions of dollars at stake, the Supreme Court’s handling of this emergency appeal will determine not just the fate of that money, but also how far presidents can go to rescind congressionally approved spending after the fact.