WASHINGTON — Sen. Susan Collins is challenging the Trump administration’s plan to create a new board with power over National Institutes of Health grant decisions, warning that political control of research funding could undermine scientific review and congressional authority. In a letter Tuesday to Office of Management and Budget Director Russ Vought and NIH Director Jay Bhattacharya, Collins urged the administration not to proceed with an executive order establishing the board. Reports of the plan followed a Friday Oval Office meeting in which President Donald Trump directed Vought to draft such an order, according to two administration officials familiar with the discussion. Under the reported proposal, Vought would have veto power over grants and Bhattacharya would serve on the board. The administration has argued that the NIH has favored progressive academics, while Collins said the proposed structure risks replacing scientific evaluation with political considerations. “Any attempt to politicize grantmaking … is contrary to congressional intent,” Collins said Monday. In her letter, she wrote that federal biomedical research should be funded according to “scientific merit and value rather than political ideology.” NIH grant applications currently undergo a lengthy peer-review process involving outside experts who assess the proposed research. Collins said that system has supported advances in research on Alzheimer’s disease, Type 1 diabetes and cancer. Her warning also invoked a stopgap spending bill Congress approved earlier this month. That legislation blocks the administration from finalizing a separate proposed rule that would have expanded political appointees’ authority over the approval of federal research grants, according to Collins. “Your proposal to establish a new committee to review NIH grants risks undermining the Congressionally-mandated peer review process that all NIH grants must undergo before they are approved for federal funding,” Collins wrote. Collins has previously opposed efforts by the Trump administration to exert greater influence over research funding. She said that if the administration wants to change how NIH grants are handled, it should submit legislation to Congress rather than attempt to do so through executive action. The Maine Republican is joined in opposing the plan by senior Democratic appropriators, including Sen. Patty Murray of Washington and Rep. Rosa DeLauro of Connecticut. They have urged other Republicans to object as well. The dispute could affect universities, medical researchers and patients who rely on federally supported studies. NIH grants finance basic and clinical research across the country, and changes to the review process could influence which studies receive support and how independent scientists participate in those decisions. The administration had not publicly announced the executive order as of Tuesday. Its next steps, and whether Congress will seek to block or limit the proposal, remained unsettled.