Trump's second presidency begins: evaluating effects on the US health system.

The first hundred days of the second Trump administration was unprecedented, with the administration taking remarkably aggressive, often questionably legal actions across health policy. This article uses the Health Systems Performance Assessment Framework to identify key policies regarding resources, financing, governance, and service delivery and their impact on the cost, quality, access, and equity of the US health system. The evaluation is largely negative. The administration, in its very energetic first hundred days, has already undermined resources, financing, and in particular governance in areas as diverse as oversight of long-term care, scientific research, and vaccination policy. Administration rhetoric and budget proposals called for severe reductions in health care access and actions to terminate services for particular groups, such as immigrants or gender minorities. Many of the particular actions, such as mass layoffs of specialist scientific and regulatory staff, will be difficult to reverse.