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.

During a 90-minute hearing about the order that was conducted over video chat last week, some justices asked tough questions of the lawyer defending the state’s top health official, Andrea Palm.

“Isn’t it the very definition of tyranny for one person to order people to be imprisoned for going to work, among other ordinarily lawful activities?” Justice Rebecca Bradley asked.

In their majority opinion on Wednesday, the justices ruled that Ms. Palm did not follow the proper procedure for setting stay-at-home limits, and should have followed a rule-making process that permits members of the Legislature to provide input.

“We do not conclude that Palm was without any power to act in the face of this pandemic,” the justices wrote. “However, Palm must follow the law that is applicable to state-wide emergencies.”

The ruling appears to leave Mr. Evers and Republican leaders of the State Legislature in a position of negotiating any next steps for limits on businesses amid the pandemic. But their work relations have been extraordinarily tense, and many observers said the possibility of fruitful negotiation seemed remote.

Mr. Evers, who has already announced plans for a gradual reopening of businesses, said that he hoped to work with Republican lawmakers on next steps, but that in the meantime, he hoped that Wisconsin residents would remain safe, and at home.

“We are in a very perilous place,” he said.

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, but that the governor’s office had, until now, kept them out of the process. “We’re more than willing to sit down with the governor,” he said.

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.”

Wisconsin is considered a swing state in November’s presidential election, and for much of the last decade it has been riven by an intense partisan battle.

When Mr. Evers was elected governor in 2018, it set off a sharp battle over the state’s direction on all sorts of policies. Republicans had full control of the state before that, during a period in which they curtailed bargaining rights for many public labor unions and moved the state sharply to the right.

The Wisconsin Supreme Court, while officially nonpartisan, has long been sharply divided along conservative-liberal lines that are well understood by the state’s voters. As partisan fights boiled over in the State Legislature, they emerged on the court as well, once leading to claims of a physical altercation between justices on opposing sides. Conservatives hold a majority on the court, and they will even after a new justice — a liberal challenger who upset Justice Kelly this spring — is seated in August.

This week’s court ruling did not provide a mechanism for a stay so that Republicans and Democrats could reach a compromise on reopening Wisconsin, which the dissenting justices wrote could endanger residents.

“The lack of a stay would be particularly breathtaking given the testimony yesterday before Congress by one of our nation’s top infectious disease experts, Dr. Anthony Fauci,” Justice Ann Walsh Bradley wrote. “He warned against lifting too quickly stay-at-home orders.”

Around the state, groups were trying to determine how the opinion would now affect life. A poll of Wisconsin residents released this week by Marquette University Law School found that 69 percent of those surveyed supported the state’s move to close schools and businesses and restrict public gatherings.

“Public health experts have been clear that prematurely lifting social distancing measures will have serious and deadly consequences, especially for vulnerable communities,” Chris Ott, the executive director of the A.C.L.U. of Wisconsin, said in a statement. He added, “Emergency orders can be necessary during crises like a pandemic, as long as they are grounded in science and consistent with the need to protect the health, safety, and civil liberties of us all.”

Rick Esenberg, the president of the Wisconsin Institute for Law and Liberty, which had filed an amicus brief siding with the Legislature, commended the court on Wednesday.

“The court’s decision ensures that Wisconsin’s response to Covid-19 must involve both the executive and the legislative branch,” Mr. Esenberg said. “Wisconsin will be better for it. The grave nature of the pandemic cannot be used to subvert our very form of government.”

Original: NEW YORK TIMES – Monica Davey and Nicholas Bogel-Burroughs contributed reporting.