An executive order signed by President Donald Trump late Thursday aims to give political appointees power over the billions of dollars in grants awarded by federal agencies. Scientists say it threatens to undermine the process that has helped make the U.S. the world leader in research and development.

The order requires all federal agencies, including FEMA, the National Science Foundation and the National Institutes of Health, to appoint officials responsible for reviewing federal funding opportunities and grants, so that they “are consistent with agency priorities and the national interest.”

It also requires agencies to make it so that current and future federal grants can be terminated at any time — including during the grant period itself.

Agencies cannot announce new funding opportunities until the new protocols are in place, according to the order. The Trump administration said these changes are part of an effort to “strengthen oversight” and “streamline agency grantmaking.” Scientists say the order will cripple America’s scientific engine by placing control over federal research funds in the hands of people who are influenced by politics and lack relevant expertise.

“This is taking political control of a once politically neutral mechanism for funding science in the U.S.,” said Joseph Bak-Coleman, a scientist studying group decision-making at the University of Washington.

The changes will delay grant review and approval, slowing “progress for cures and treatments that patients and families across the country urgently need,” said the Association of American Medical Colleges in a statement.

The administration has already terminated thousands of research grants at agencies like the NSF and NIH, including on topics like transgender health, vaccine hesitancy, misinformation and diversity, equity and inclusion.

The order could affect emergency relief grants doled out by FEMA, public safety initiatives funded by the Department of Justice and public health efforts supported by the Centers for Disease Control. Experts say the order is likely to be challenged in court.