The law, which took effect in August, bars Missouri state officials and local authorities from enforcing federal gun laws. The Justice Department alleged in its complaint that the state law “uniquely discriminates against federal agencies and employees; impedes law enforcement efforts in Missouri; and violates the Supremacy Clause of the Constitution of the United States”.
Republican Missouri Governor Mike Parson did not immediately respond to CNN’s request for comment.
In some cases, police departments have withdrawn their officers from task forces led by federal law enforcement agencies.
“Missouri’s law has had a detrimental impact on public safety efforts within the state. Prior to the enactment of HB 85, Missouri state and local law enforcement officers routinely worked side by coast with federal agents to keep Missourians safe. They have done so by sharing (among other things) evidence, data and other information critical to law enforcement and participating in task forces spouses on federal and state law enforcement,” the Justice Department complaint alleged.
“The HB 85, however, now severely impedes federal criminal law enforcement operations in the state of Missouri.”
Most disputes raised by the law have arisen in operations involving the Bureau of Alcohol, Tobacco, Firearms and Explosives, which enforces gun laws, Justice Department officials say . But other federal law enforcement agencies have also encountered issues that hamper cases requiring federal assistance.
CNN previously reported that, in one case, U.S. Marshals preparing for an operation with local police to arrest a fugitive allegedly involved in drug trafficking faced a series of last-minute hurdles due to the law.
“A state cannot simply declare federal laws invalid,” Assistant Deputy Attorney General Brian Boynton said in a statement Wednesday. “This legislation makes it difficult to enforce federal gun laws and strains the important law enforcement partnerships that help keep violent criminals off the streets.”
CNN’s Emma Tucker and Evan Perez contributed to this report.