The Wisconsin Supreme Court on Wednesday rejected the extension of the state’s stay-at-home order, siding with Republican legislators in a high-profile challenge of the emergency authority of a statewide official during the coronavirus pandemic.

Gov. Tony Evers, a Democrat, had extended the prohibition on most travel and operations of nonessential businesses until May 26. But in a 4-to-3 ruling, the court said that Wisconsin’s top health official had not followed the proper process in setting the strict limits for residents.

Although the opinion centered on the technical method by which the limits had been set, several conservative justices conveyed their dismay at the restrictions themselves.

“This comprehensive claim to control virtually every aspect of a person’s life is something we normally associate with a prison, not a free society governed by the rule of law,” Justice Daniel Kelly wrote in a concurring opinion.

The ruling, Mr. Evers’s office said, appears to immediately end statewide provisions that have required many Wisconsin residents to stay home. Within hours of the ruling, some taverns were making plans for reopening, the governor’s office said.

“This turns the state to chaos,” Mr. Evers said in an interview. “People will get sick. And the Republicans own the chaos.”

More than 10,000 cases of the coronavirus have been identified in the state, a New York Times database shows, and at least 421 people have died.

There have been legal challenges to stay-at-home orders in Michigan, California, Kentucky and Illinois, but none of those were successful in persuading a court to fully strike down the order, as the plaintiffs in the Wisconsin case were. Wisconsin’s stay-at-home order took effect on March 25 and was extended by the governor on April 16, leading to a protest at the State Capitol.

Scott Fitzgerald, the leader of the Republican majority in the Wisconsin Senate, said lawmakers had long been seeking a voice in the conversation about how to respond to the pandemic.

For the moment, Mr. Fitzgerald said, residents would use their own judgment. “People understand, if you don’t want to go to church, you don’t go to church,” he said. “If you don’t want to go to work, you don’t go.”