COLUMBIA, Mo. (AP) — Federal appellate judges overturned a Missouri law Monday that banned police from enforcing some federal gun laws.

The 8th U.S. Circuit Court of Appeals found the Missouri law violated a section of the U.S. Constitution known as the supremacy clause, which asserts that federal law takes precedence over state laws.

“A State cannot invalidate federal law to itself,” 8th Circuit Chief Judge Steven Colloton wrote in the ruling.

Missouri’s Republican Attorney General Andrew Bailey said in a statement that his office was reviewing the decision. “I will always fight for Missourians’ Second Amendment rights,” he said.

The U.S. Justice Department, which filed the lawsuit against Missouri, declined to comment.

The Missouri law forbade police from enforcing federal gun laws that don’t have an equivalent state law. Law enforcement agencies with officers who knowingly enforced federal gun laws without equivalent state laws faced a fine of $50,000 per violating officer.

Federal laws without similar Missouri laws include statutes covering weapons registration and tracking, and possession of firearms by some domestic violence offenders.

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Missouri’s law has been on hold since 2023, when the U.S. Supreme Court temporarily blocked it as the legal challenge played out in lower courts.

Conflict over Missouri’s law wrecked a crime-fighting partnership with U.S. attorneys that Missouri’s former Republican attorney general — Eric Schmitt, now a U.S. senator — touted for years. Under Schmitt’s Safer Streets Initiative, attorneys from his office were deputized as assistant U.S. attorneys to help prosecute violent crimes.

The Justice Department had said the Missouri state crime lab, operated by the Highway Patrol, refused to process evidence that would help federal firearms prosecutions after the law took effect.

Republican lawmakers who helped pass the bill said they were motivated by the potential for new gun restrictions under Democratic President Joe Biden, who had signed the most sweeping gun violence bill in decades.

The federal legislation toughened background checks for the youngest gun buyers, keeps firearms from more domestic violence offenders, and helps states put in place red flag laws that make it easier for authorities to take weapons from people judged to be dangerous.