President Donald Trump is canceling nearly $1 billion in spending approved by Congress, with the White House announcing Friday that the administration would use a rare and contested authority to strip funding from immigrant services and diversity focused initiatives.

Trump’s Office of Management and Budget framed the rescissions as an attack on “the most harmful government spending.” The administration presented the cuts as eliminating unnecessary programs, but the maneuver immediately raised alarms over Congress’s constitutional spending power.

Most of the reductions target Health and Human Services programs serving refugees and unaccompanied minors accused of being in the country illegally. The administration maintains that the money is no longer needed because illegal border crossings have diminished considerably.

Other targets include a Department of Education program serving migrant students and a Department of Justice office focused on reducing racial tensions. The administration also moved against housing counseling services, an initiative supporting minority entrepreneurs, and several Health and Human Services grants.

The administration called some of those grants “outright harmful and blatantly ideological.” A White House press release also noted that some organizations affected by the rescissions are led by people who worked in the administration of Democratic President Barack Obama.

Sen. Susan Collins of Maine, the Republican chair of the Senate Appropriations Committee who faces a tough reelection campaign, condemned the move. Collins said the administration acted without warning or consultation, and she pledged to work with colleagues to address “these illegal actions.”

“Not only is the delay itself an impoundment that was not reported to Congress, but also it is a usurpation of Congress’s appropriations powers,” Collins said. “OMB is an agency of the executive branch. It does not get to decide which programs are worth funding.”

Federal law gives Congress 45 days to review proposed presidential spending cuts before they take effect. Trump announced the rescissions with only five days remaining in the federal fiscal year, while the House is out of session through the November election.

That timing made meaningful congressional review all but impossible. The Government Accountability Office, an arm of Congress, considers the maneuver known as a “pocket rescission” illegal, while Collins called it the latest OMB attempt to “undermine Congress’s Constitutional power of the purse.”

A year ago, Trump issued a pocket rescission for the first time in nearly 50 years, blocking $4.9 billion in congressionally approved foreign aid. The U.S. Supreme Court declined to stop those rescissions, saying Trump’s authority over foreign affairs weighed heavily in its decision.

This year, however, Trump is targeting domestic spending. The White House argues that pocket rescissions are legally permissible despite uncertainty surrounding the practice, pointing to a 1977 episode involving then Democratic President Jimmy Carter and a proposal submitted well before the 45 day deadline.

The maneuver fits a broader pattern of the Trump administration asserting greater control over the federal government while eroding congressional authority. The administration has also fired federal workers, imposed a historic increase in tariffs, and started the war in Iran without going through Congress, leaving courts to determine the limits of presidential power.

Sen. Patty Murray of Washington, the leading Democrat on the Senate Appropriations Committee, called the White House action “theft from the American people, plain and simple.” She said the money was approved on a bipartisan basis and should be helping people rather than being blocked by the president.

“These are funds Congress has delivered on a bipartisan basis and should be helping people—not cut off by a president more focused on building a ballroom than investing in families,” Murray said. She added that Republicans had refused Democratic efforts to include protections against the administration usurping congressional spending authority.

“While Trump spends tax dollars on ads promoting himself, Congress needs to reassert its powers to help people, and it’s past time Republicans join us in that fight,” Murray said. Her criticism placed the dispute squarely on Congress’s responsibility to protect its control of federal spending.

The White House said the rescissions also include $70 million for international education programs it labeled “woke,” $28 million in Health and Human Services research grants, and $9 million in debt relief for foreign countries funding climate policies. Another $10 million is being withheld from a minority business development program.