Over the last 16 years, presidential administrations of both parties have wielded the power of the Education Department not to just carry out congressional legislative directives but also to make their own policies—reshaping the federal government’s role in higher education. But future administrations likely won’t be rewriting regulations in the same way after the Supreme Court on Friday ended a 40-year precedent under which federal courts deferred to agencies’ interpretations of ambiguous statutes. Chief Justice John Roberts Jr. wrote in the majority opinion that the deference to agencies known as the Chevron doctrine “cannot be reconciled” with the federal law dictating how the executive branch writes policies. Instead, federal judges should be empowered to determine whether a regulation complies with federal law.