In this episode of Unwritten Law, NCLA’s Mark Chenoweth and John Vecchione explore a major development in Congress involving the Congressional Review Act (CRA).

The Senate is preparing to vote on whether to overturn California’s EPA waiver, which allows the state to impose stricter vehicle emissions standards than the federal government. Mark and John break down why this obscure but powerful legislative tool matters, how California’s rules affect carmakers and consumers nationwide, and why this CRA vote could set up a legal showdown with sweeping consequences.

They also discuss how a little-known clause banning “substantially similar” regulations could haunt future agency actions—and why this case might finally test that theory in court.