The Illinois Supreme Court has upheld the state's ban on the sale or possession of semiautomatic weapons used in mass killings across the country. In a 4-3 decision on Friday, the court ruled that the Protect Our Communities Act does not violate the federal Constitution's guarantee of equal protection of the law or the state constitution's prohibition on special legislation. The court also determined that State Rep. Dan Caulkins, a Republican from Decatur, and other gun owners who brought the lawsuit had waived their claims that the law infringes upon the Second Amendment.

However, the Second Amendment claim is still alive in several federal lawsuits filed in southern Illinois, which have been consolidated and are awaiting action in an appeals court. The law bans numerous specific brands or types of rifles and handguns, as well as .50-caliber guns, attachments, and rapid-firing devices. It imposes a limit of 10 rounds for rifles and 15 rounds for handguns. One of the most popular guns targeted by the ban is the AR-15 rifle, which is estimated to be present in at least 25 million American households, according to research by Georgetown University in 2021.

The Protect Our Communities Act was signed into law by Democratic Governor J.B. Pritzker in January, shortly after it was passed by lawmakers in a lame-duck session. The law was prompted by a mass shooting in Highland Park in 2022, where a shooter using a high-powered rifle killed seven people and injured dozens. The law has faced significant criticism from gun-rights advocates, including county sheriffs who have stated their reluctance to enforce it.

Caulkins and other gun owners argued that the semiautomatic ban violates their right to possess guns, citing the U.S. Supreme Court's 2022 ruling that Americans have a right to carry weapons in public for self-defense. They also claimed that the law violates the Constitution's guarantee of equal protection and the state constitution's provision against "special legislation" when a "general law is applicable." A lower court agreed with these arguments in March.

The lawsuit alleges that the law was applied unequally, as individuals who possessed semiautomatic weapons before the law took effect are allowed to keep them, although they are restricted from selling or transferring them. These individuals must register their guns with the Illinois State Police by January 1, 2024. The ban also provides exemptions for law enforcement officers, including retired officers, and on-duty military personnel. Critics have contended that many civilians have more experience and training in handling semiautomatic weapons than law enforcement officers.

The Illinois Supreme Court's decision comes in the midst of several other lawsuits against the ban that have been filed in federal court. These cases have been consolidated and are awaiting action in an appeals court. It remains to be seen whether the Illinois high court's ruling will provide answers to the questions raised in the federal lawsuits.

In response to the decision, Governor Pritzker expressed satisfaction, stating that the Protect Our Communities Act is a common-sense gun reform law aimed at keeping "mass-killing machines" off the streets and protecting the safety of Illinois residents. He believes that the law preserves the state's leading legislation in combating gun violence and saving lives.