The U.S. Environmental Protection Agency released a final rule on September 19, 2019, eliminating California’s right to create its own greenhouse gas emission standards for cars and other vehicles. The Trump administration’s decision affects more than just California – 13 other states and the District of Columbia have also adopted California’s more stringent emission rules for cars and trucks. Just one day after the final rule was released, California and 22 other states fought back by filing a lawsuit against the National Highway Traffic Safety Administration to stop the Trump administration from revoking California’s authority to set its own vehicle emission standards.

The Trump administration’s decision to revoke the legal waiver granted to California by the Obama administration under the authority of the 1970 Clean Air Act, which allowed California to set stricter state standards for vehicle emissions standards, represents an abrupt departure from the past, given that the federal government has allowed California to set its own rules regarding emission standards for cars and trucks since the 1970s.

California’s lawsuit represents what is likely to turn into an intense legal battle over states’ rights and climate change and will likely only be resolved once it reaches the Supreme Court. The outcome decided there could have long-reaching effects that may ultimately trigger extensive impacts affecting states’ control over their own environmental laws and the volume of pollution produced by the United States.