US President Donald Trump's administration has asked the Supreme Court to let it withhold more than $4bn (£3bn) in foreign aid.
The administration is seeking an emergency order as it tries to claw back funds for foreign assistance programmes that have already been allocated by Congress.
A lower court last week stated that the Trump administration had a statutory obligation to spend the money, and an appeals court declined last Friday to freeze that ruling.
The president attempted to use a rarely employed legislative tool to withdraw the funds. Since returning to the White House, Trump has cancelled billions in foreign aid that he claims contradicts his objectives.
Solicitor General D John Sauer argued in Monday's filing that the lower court's injunction raises a grave and urgent threat to the separation of powers. He maintained that the President cannot effectively communicate in foreign affairs when compelled to advocate against his own policies due to court requirements.
The Supreme Court could issue a ruling at any moment. Judge Amir Ali had previously mandated that the US government must spend the allocated funds unless Congress votes to upend Trump's request.
On 28 August, Trump informed the House of Representatives that his administration would not spend billions in foreign aid approved by Congress earlier this year. The funds include approximately $3bn for the US Agency for International Development (USAID) and contributions towards international peacekeeping and democracy promotion.
Trump, who is a Republican, has been dismantling USAID since he labels its spending as wasteful.
To retrieve the foreign aid funds, he is invoking a legislative process known as pocket rescission under the Impoundment Control Act, which empowers the President to ask for cancellation of Congress-approved expenditures.
However, such a late notice in the fiscal year could result in the funds going unspent as Congress does not have sufficient time to act on the request.
A coalition of nonprofits and businesses that rely on foreign assistance funding has filed a legal challenge against this motion, marking an unprecedented instance of a president unilaterally attempting to recover allocated funding.
The Trump administration has declared intentions to still spend another $6.5bn in foreign aid despite ongoing lawsuits from aid groups.
This clash over foreign aid funding has significant historical context; in March, the Supreme Court declined Trump's request to retain $2bn in frozen foreign aid during ongoing litigation—a decision met with a narrow 5-4 ruling.
