President Donald Trump has notified Congress he is moving to cancel $4.9 billion in congressionally approved foreign aid using a rare “pocket rescission,” drawing criticism from Democrats and at least one top Republican senator who questioned the legality of the move.

The 1974 Impoundment Control Act gives the president the authority to propose canceling funds approved by Congress. Congress can vote on pulling back the funds or sustaining them, but by proposing the rescission so close to Sept. 30 the White House ensures that the money won’t be spent and the funding lapses.