The Justice Department is warning Missouri officials that the state can’t ignore federal law, after the governor signed a bill last week that bans police from enforcing federal gun rules.

In a letter sent Wednesday night and obtained by The Associated Press, Justice officials said the U.S. Constitution’s Supremacy Clause outweighs the measure that Gov. Mike Parson signed into law Saturday. The new rules penalize local police departments if their officers enforce federal gun laws.

Acting Assistant Attorney General Brian Boynton said the law threatens to disrupt the working relationship between federal and local authorities, they said in the letter, noting that Missouri receives federal grants and technical assistance.

“The public safety of the people of the United States and citizens of Missouri is paramount,” Boynton wrote in the letter.

President Joe Biden has made gun control laws a priority of his administration, and the House has passed two bills requiring background checks on firearms sales and an expanded review for gun purchases, though they face a tough road in the Senate. But states, including Missouri, have increasingly worked to loosen gun laws, including abandoning requirements that people get training and pass background checks to carry concealed handguns.

Missouri’s law would subject law enforcement agencies with officers who knowingly enforce any federal laws to a fine of about $50,000 per violating officer.

Republican lawmakers who worked to pass the bill have said they were motivated by the potential of more restrictive gun laws in the Biden administration. But state Democrats have argued the law is unconstitutional and have predicted it would not pass a challenge in the courts.

The Justice Department argued in the letter that the state lacks the authority to shield any Missouri businesses or citizens from federal law or to prevent federal law enforcement officials from carrying out their duties.

Boynton said the bill “conflicts with federal firearms laws and regulation” and federal law would supersede the state’s new statute. He said federal agents and the U.S. attorney’s offices in the state would continue to enforce all federal firearms laws and regulations. He asked that Parson and Eric Schmitt, the state’s attorney general, clarify the law and how it would work in a response by Friday.

Six states have passed legislation removing or weakening concealed-carry permit requirements this year, most recently Texas, where Republican Gov. Greg Abbott signed a bill Wednesday. About 20 states now allow people to carry concealed weapons without a license. At least three other states have passed legislation banning police from enforcing federal gun laws, a preemptive shot at any new measures passed by Democrats.

(AP)