President Trump is seeking to claw back roughly $5 billion in congressionally approved funding for foreign aid programs using a “pocket rescission,” a rare use of presidential power that is likely to spur backlash on Capitol Hill and potential legal challenges.

Trump made the request in a letter sent to Speaker Mike Johnson (R-La.) late Thursday. The White House is aiming to cut $4.9 billion in funds allocated to the State Department and the U.S. Agency for International Development (USAID), an international aid effort that has been dismantled by the Trump administration.

The Impoundment Control Act (ICA) lays out rules governing that process and allows the administration to temporarily withhold funding for 45 days while Congress considers the request. If lawmakers opt not to approve the request, the funds must be released. 

A pocket rescission would see the president send the same type of request to Congress within 45 days of the end of the fiscal year on Sept. 30. The request is made so late that the funding is essentially paused until it runs out at the end of the year regardless of congressional action.

The New York Post first reported on Trump’s plans to use the pocket rescission, which has not been done in nearly 50 years and may face legal challenges seeking to define Congress’s power over federal spending.

The outlet reported the president is aiming to cut roughly $3 billion in funding for USAID, plus an additional roughly $900 million in State Department funds and $445 million in separate peacekeeping aid.

A spokesperson for the Office of Management and Budget pointed to the last time a pocket rescission was used, in 1977 by then-President Jimmy Carter.

The spokesperson said the Government Accountability Office provided recommendations at the time for how Congress could amend the law to prevent future pocket rescissions. But because no amendments were made, the spokesperson said, it remains a lawful tool for the executive branch.

The GOP-led Congress in July passed the White House’s initial rescissions request, which targeted a total of $9 billion in funding for global aid programs and the Corporation for Public Broadcasting, which funds National Public Radio and PBS, organizations Trump and his allies have accused of liberal bias.

The Trump administration has targeted government spending for cuts it has deemed wasteful or unaligned with the president’s “America first” agenda. But some lawmakers have expressed reservations about ceding the power of the purse to the administration to revoke previously approved funding.