A coalition of two dozen states has mounted constitutional challenges against a Trump administration policy that would impose federal standards on mail ballot eligibility, drawing a sharp line around one of democracy's most contested questions: who holds the authority to determine how citizens cast their votes. The dispute reaches into the deep architecture of American federalism, where the boundary between federal power and state sovereignty over elections has never been fully settled. What unfolds in the courts may redefine the landscape of voting access before the next election cycle arrive