The Democratic governor of Illinois, J.B. Pritzker, appears headed for a showdown with many of his state’s local law enforcement officers over a new gun control measure signed by the possible presidential aspirant.

At least 80 sheriffs across the state are vowing to ignore the new law, which bans many brands of semi-automatic rifles, puts limits on the capacity of ammunition magazines, and requires residents who own semi-automatic weapons to register them or face misdemeanor charges.  

The measure, passed by the Illinois state legislature and signed by Mr. Pritzker January 10, has gun rights advocates lining up to challenge it in court. The Illinois State Rifle Association has already issued a call for plaintiffs to challenge a law that it calls clearly unconstitutional.

Mr. Pritzker “signed into law a draconian bill that squashes the rights of 2.4 million plus law-abiding firearm owners in Illinois,” the organization stated. “The bootheel of government has been placed squarely on the neck of freedom-loving Illinois citizens.  The rights of people who have done nothing wrong have been trampled.”

A sheriff in Monroe County, south of St. Louis, Neal Rohlfing, was among the 80 or so sheriffs from across the state who said they would not enforce the new law. In a letter posted to the department’s Facebook page, Mr. Rohlfing said he has sworn to uphold his constituents’ constitutional rights, including their Second Amendment rights.

“As the custodian of the jail and chief law enforcement official for Monroe County, neither myself nor my office will be checking to ensure that lawful gun owners register their weapons with the State, nor will be arresting or housing law abiding individuals that have been arrested solely with non-compliance of this Act,” the letter said.

In an appearance on MSNBC, Mr. Pritzker accused the sheriffs, who are elected officials in Illinois, of “political grandstanding” to score points with conservative voters. He said he was confident the new law will withstand the inevitable legal scrutiny and insisted that it will be enforced with or without their assistance.

“It’s our state police and law enforcement across the state that will, in fact, enforce this law, and these outlier sheriffs will comply or, frankly, they’ll have to answer to the voters,” Mr. Pritzker said.

The ban immediately outlawed the sale or purchase of “assault-style” semi-automatic and .50-caliber rifles. The legislation listed 60 such models and takes aim at all “AR-style” weapons that have detachable magazines and pistol grips. Such weapons have been used in a number of high-profile mass shootings, including one in Highland Park, Illinois last summer that prompted the legislation.

The law also bans magazines holding more than 10 rounds for long guns and 15 rounds for pistols. Illinois residents who already own the banned firearms or high-capacity magazines are required to register them with local law enforcement, and provide serial numbers, by January 1, 2024.

At least eight states, along with the District of Columbia, have similar bans on the books, among them California, Connecticut, Massachusetts, New York and New Jersey. Three other states — Virginia, Minnesota, and Washington — have passed strict regulations on the weapons but not banned them outright. A number of local jurisdictions around the country, including Cook County in the Chicago area, have similar rules covering the rifles.

Legal experts consulted by the Chicago Tribune agreed with the state rifle association’s assessment that portions of the law are “clearly unconstitutional,” especially in light of the Supreme Court’s ruling last summer in the New York Rifle and Pistol Association v. Bruen case that dramatically expanded Americans’ Second Amendment rights. A UCLA law professor and gun rights scholar, Adam Winkler, told the paper that the law “is going to be challenged, and there is a good chance it will be overturned.”