A federal judge on Tuesday struck down a controversial Missouri law — known as the Second Amendment Preservation Act — that penalizes police for enforcing federal gun laws.

U.S. District Court Judge Brian Wimes ruled that the 2021 Missouri law is unconstitutional and “invalid, null, void, and of no effect.”

“State and local law enforcement officials in Missouri may lawfully participate in joint federal task forces, assist in the investigation and enforcement of federal firearm crimes,” Wimes wrote in his decision, “and fully share information with the federal government without fear of… penalties.” 

Last year, the U.S. Department of Justice filed a lawsuit arguing Missouri’s law has undermined federal drug and weapons investigations.

Among its provisions, the law says law enforcement agencies will face $50,000 fines if they “infringe” on Missourians’ Second Amendment rights.

Some of those laws would include imposing certain taxes on firearms, requiring gun owners to register their weapons and laws prohibiting “law-abiding” residents from possessing or transferring their guns.

Frederic Winston, special agent in charge of the Kansas City Field Division of the Bureau of Alcohol, Tobacco, Firearms and Explosives (ATF), said in an affidavit submitted to the court in a separate lawsuit that a dozen state and local officers have withdrawn from participating in ATF task forces at least in part because of the law.

That includes members of the Missouri State Highway Patrol, Columbia Police Department, Johnson County Sheriff’s Office, O’Fallon Police Department and Sedalia Police Department.

Federal law cannot be nullified by any state law, Wimes wrote in his ruling, and Missouri legislators are aware of that.

“SAPA is an unconstitutional ‘interposit[ion]’ against federal law and is designed to be just that,” Wimes wrote.

In the ruling, he said the law’s practical effects are counterintuitive to its stated purpose. 

“While purporting to protect citizens,” Wimes writes, “SAPA exposes citizens to greater harm by interfering with the federal government’s ability to enforce lawfully enacted firearms regulations designed by Congress for the purpose of protecting citizens within the limits of the constitution.”

In a statement on social media, Missouri Attorney General Andrew Bailey said his office will appeal the decision, and he anticipates “a better result” at the Eighth Circuit Court of Appeals.

“If the state legislature wants to expand upon the foundational rights codified in the Second Amendment, they have the authority to do that,” Bailey stated. “But SAPA is also about the Tenth Amendment. It’s about federalism and individual liberty.”

Wimes addressed this argument in his ruling.

“The Missouri General Assembly’s assertion that the Supremacy Clause does not extend to acts of Congress,” Wimes states, “does not make it so.”

This story has been updated since it was originally published.