The Supreme Court on Friday kept on hold a Missouri law that bars police from enforcing federal gun laws, rejecting an emergency appeal from the state.

The 2019 law was ruled unconstitutional by a District Court judge but allowed to remain in effect. A federal appeals court then blocked enforcement while the state appeals the District Court ruling.

Missouri had wanted the law to be in effect while the court fight plays out.

Justice Clarence Thomas was the only member of the court to side with Missouri on Friday.

The law would impose a fine of $50,000 on an officer who knowingly enforces federal gun laws that don’t match up with state restrictions.

Federal laws without similar Missouri laws include registration and tracking requirements and possession of firearms by some domestic violence offenders.

The court expanded gun rights in a 2022 decision authored by Thomas. It is hearing arguments next month in the first case stemming from last year’s ruling. An appeals court invalidated a federal law that aims to keep guns away from people facing domestic violence restraining orders.