SPRINGFIELD, Ill. (AP) — The U.S. Supreme Court declined on Monday to hear a second Illinois case challenging the state’s ban on semiautomatic weapons, which took effect Jan. 1.

Decatur Republican state Rep. Dan Caulkins appealed last summer’s ruling by the Illinois Supreme Court upholding the prohibition on handguns and rifles of the type used in the 2022 Highland Park Independence Day parade shooting that killed seven and injured more than 30. Under the ban, no one may possess or manufacture nearly 200 types of the firearms or accompanying high-capacity magazines, and those who already own such guns are required to register them with the Illinois State Police.

Caulkins and his co-plaintiffs — a Decatur pawn broker and individual gun owners from the area — wanted the U.S. Supreme Court to review their claim that two state court justices, by their participation in the opinion, violated the 14th Amendment guarantee of equal protection of the laws.

They said Justices Elizabeth Rochford and Mary Kay O’Brien should have recused themselves because they accepted campaign contributions from advocates of gun restrictions, including the Gun Violence Prevention political action committee and Democratic Gov. J.B. Pritzker, who has repeatedly denied he expected anything in return for his financial support.

“Judges must preserve both the reality and appearance of impartiality,” Caulkins said. “It is impossible for these justices to be impartial after accepting millions of dollars in campaign cash from gun-control advocates and after receiving the support of a radical organization like G-PAC.”

Rochford wrote the court’s opinion, which dismissed Caulkins’ claim that the law is unconstitutional in part because it carves out exceptions for some categories of people, such as retired police officers, allowing them to keep their semiautomatic guns. O’Brien dissented for that very reason, calling it illegal special legislation.

The U.S. Supreme Court declined to hear another case on the issue last month. The case came from a federal appeals court in Illinois that recognized the legitimacy of delineating a difference between weapons suitable for military use or other “trained professionals” and those for civilians.

Caulkins and the other plaintiffs’ attorney, Jerrold Stocks, of Decatur, noted that several other cases are in line for court decisions that could land at the high court, particularly those with direct 2nd Amendment challenges to the law.

Caulkins and Stocks said they are considering legal options, which includes seeking a state court rehearing, but declined to elaborate further.

At least 10 states plus the District of Columbia have prohibitions on semiautomatic firearms.