A proposed rule from the administration of Donald Trump grants political appointees sweeping control over US research grants and allows the executive branch to override scientific peer review.Scientists including Mark Albers of Mass General Brigham and Carmen Guerra warn that the rule’s domestic-first restrictions will curtail international collaborations with institutions such as Harvard Medical School, Massachusetts Institute of Technology, Imperial College London and the University of Haifa and jeopardize trials and data sharing.The proposal has drawn nearly 280K public comments and bipartisan criticism and faces likely legal challenges, but experts say the uncertainty will slow clinical trials and disrupt long-term research even if courts intervene.