The Donald Trump administration on Monday asked the U.S. Supreme Court to allow a “freeze” on spending $4 billion in foreign aid that had been approved by Congress. The development follows a federal judge’s ruling forcing the government to spend the money, despite Trump informing Congress that he did not intend to do so.

In the new memo, Attorney General D. John Sauer argued that the case poses “a serious and urgent threat” to the power of the presidency. Under the Constitution, Congress has the power to allocate funds that the president can spend. Current federal funding expires on September 30. The Trump administration is seeking to “freeze” $4 billion in foreign aid, but says it is ready to allocate the remaining $6.5 billion that Congress has authorized.

Central to the legal dispute is federal judge Amir Ali, who ruled that the government must spend the money unless Congress approves Trump’s request for a “freeze”.