Michigan school districts can ban firearms on campus, the state's Supreme Court ruled Friday.
State law allows people with concealed firearms permits to bring guns onto school property, but at least two districts enacted policies banning weapons.
Separate lawsuits were filed by firearm advocacy groups against the Ann Arbor and Clio school districts.
On Friday, four of seven justices ruled in the schools' favor.
"We feel like it's a great day for Michigan children," Jeanice Swift, superintendent of the Ann Arbor Public Schools, said. Swift said the policy, which is tied to a city ordinance about school disruptions, was enacted after someone legally carried a gun into a choir concert in March 2015.
After the incident "our board took a courageous stand to enact a set of policies to quantify the presence of a firearm as a disruption to the classroom environment," she said.
A lawyer for Michigan Gun Owners said he was shocked by the ruling and he thought the majority justices fit the ruling to match their opinions that firearms don't belong in school.
"This did nothing to enhance school safety," attorney James Makowski said. "All they did was create a bunch of soft targets. Before this, there was at least a chance that there might be a responsibly armed citizen in a school in the state of Michigan. We just sent a message to every crazy out there."
The justices in the majority wrote that the Michigan Legislature can preempt school districts from enacting gun bans but has not done so. It cited a prior case that found the law "expressly preempts regulation of firearms by a city, village, township, or county; it does not apply to school districts."
The state's chief justice, Stephen Markman, wrote in his dissent that schools could not prohibit what state law permits. He cited code that says school districts "may exercise a power ... except as otherwise provided by law."
The other two justices wrote an opinion agreeing in part with the majority and dissenting in part.
Makowski said the Supreme Court's decision cannot be appealed, so his group is considering other action, like lobbying the legislature for a change to law. He added that like the school systems, his group wants to protect school children.
"It's just our position is that you need more resources than what the school districts have and we need to look elsewhere," he said.
The city of Ann Arbor filed an amicus brief in support of the school system. Mayor Christopher Taylor said Saturday that people with guns create an environment of fear.
"I think that it is proper to enable school districts to keep students and visitors safe," he said. "The presence of guns is a danger."