A federal judge has temporarily blocked a Missouri law that would have placed additional requirements on Obamacare’s so-called navigators, groups that have received federal funding to help people sign up for coverage under the law.

U.S. District Judge Ortie Smith issued a preliminary injunction blocking enforcement of the navigator law. He suggested in his opinion that Missouri lawmakers did not have the authority to regulate the activities of navigators who were working on behalf of HealthCare.gov, the insurance marketplace run by the federal government, which is serving Missouri and 35 other states.

“The Court is of the view that any attempt by Missouri to regulate the conduct of those working on behalf of (HealthCare.gov) is preempted,” Smith wrote in his order. “Missouri has opted not to be in the health insurance exchange business.”

“Having made the choice to leave the operation of the exchange to the federal government, Missouri cannot choose to impose additional requirements or limitations on the exchange,” Smith said. He added that those challenging the law “are likely to prevail” with their argument that the navigator law is preempted by federal statute.

According to Bloomberg BusinessWeek, the Missouri law would have subjected navigators to additional licensing tests, doubled training time requirements and imposed fines of up to $1,000 for non-compliance.

One of the lawyers challenging the law told the news outlet that the ruling could spell trouble for other states that have imposed burdensome requirements on the navigators operating in their borders. Florida and Texas are some of the other states that have adopted additional rules for navigators, and they also defaulted to the federal website.

“On this the court is clear: federally funded navigators must be able to exercise the duties they are funded to do under federal law,” the attorney, Jane Perkins, said.

The full opinion, issued Thursday, is below.

Missouri Obamacare Navigators Order