The U.S. Supreme Court will decide soon whether to take up a critical issue for San Francisco, other cities across the country and their homeless populations: whether people can be evicted from street camps without an offer of available shelter.

Gov. Gavin Newsom wants the court to overturn an appeals court decision that requires cities to have adequate shelter space available before sweeping homeless encampments. San Francisco Mayor London Breed says the ruling has undermined the city’s “compassionate attempts to address the homelessness crisis.”

A federal magistrate has relied on the appellate ruling as authority for an order prohibiting San Francisco from removing thousands of unhoused people from city streets until it gives them somewhere else to live. Advocates for the homeless say the ruling is essential for their lives and well-being, but the city — and local and state governments across California and the nation — say it is making their areas less healthy, attractive and livable.

“A town that is not allowed to keep its sidewalks clear and parks open is not really a town at all. It is just a cluster of people living close together,” the National League of Cities, the National Association of Counties and other local governments told the Supreme Court.

Lawyers for Los Angeles and Orange County, police groups, prosecutors and business organizations have also asked the court to reject the appeals court’s restrictions on removing homeless encampments.

And a group of 20 states, led by Idaho, wants the court to go even further and use the case to repeal the constitutional standard it set in 1958, in an opinion by Chief Justice Earl Warren, to rely on “evolving standards of decency” when deciding whether actions by government officials or police violate the Eighth Amendment’s ban on cruel and unusual punishment.

All told, 25 groups of state and local governments, businesses and other advocates have asked the Supreme Court to review and reverse the September 2022 decision by the 9th U.S. Circuit Court of Appeals in a case from Grants Pass, Ore., and the same court’s 2018 ruling in a Boise, Idaho, case.

Though their impact is disputed, the rulings essentially bar a city, under the Constitution’s Eighth Amendment standards, from evicting camp residents who have nowhere else to go.

Does that mean a city must have enough shelter beds for its entire homeless population before clearing an encampment? San Francisco officials say the appeals court has set a virtually impossible standard, but advocates for the homeless say the city simply has to offer available shelter to individuals before evicting them, even if it doesn’t have enough beds for everyone.

A homeless person could still refuse to leave for legitimate reasons — for example, disabilities that could not be accommodated in the shelter that was offered — but otherwise could be removed from the street and arrested for staying put.

San Francisco’s lawyers said its officers were evicting people who had declined offers of shelter. But in her injunction against encampment sweeps last December, U.S. Magistrate Judge Donna Ryu said the city’s shelters were full and had closed their waiting lists.

The city is appealing Ryu’s order in a separate case, and the 9th Circuit has allowed the injunction to remain in effect for now. But its legal basis could be undermined if the Supreme Court agreed to review and reverse the Grants Pass ruling.

The Supreme Court is scheduled to consider the case at its internal conference on Friday, but seems unlikely to announce immediately whether it will grant review, since it has given lawyers for Grants Pass until Dec. 6 to reply to the filings.

The justices denied review of the Boise case in 2019, leaving the 9th Circuit ruling in place and binding on federal courts in California and eight other Western states. It could also affect cases elsewhere, as indicated by filings from states and organizations outside the 9th Circuit.

But the Supreme Court’s conservative majority has been bolstered since 2020 with President Donald Trump’s appointment of Amy Coney Barrett to replace the late Justice Ruth Bader Ginsburg. And Justice Clarence Thomas, joined at times by fellow conservatives, has argued in use-of-force cases that the court’s test for cruel and unusual punishment is far stricter than the drafters of the Constitution intended in 1791.

The prospect of the court taking up the case, and rewriting its constitutional standards, is “very concerning” in view of some of its recent rulings, said Zal Shroff, acting legal director of the Lawyers’ Committee for Civil Rights of the San Francisco Bay Area and an attorney for the Coalition on Homelessness in the ongoing San Francisco case.

“California needs to address the homelessness crisis by providing real access to affordable housing and shelter for Californians struggling to make ends meet,” Shroff told the Chronicle. “But arresting thousands just because they cannot find shelter, making it illegal to be homeless, and summarily destroying tents because politicians wish to conceal the extent of our affordable housing crisis is fundamentally unconstitutional, not to mention morally repugnant.”

Lawyers for Breed and the city have asked the Supreme Court not merely to review the Grants Pass case but to take the unusual step of overturning it immediately.

Newsom did not go that far, seeking only review of the case, but argued through his lawyers that the Grants Pass ruling and others since the 2018 Boise case have prevented cities “from imposing common-sense time and place restrictions to keep streets safe and to move those experiencing homelessness into shelter.”

The lawyers represented only Newsom, as state Attorney General Rob Bonta has not filed arguments on either side of the case. On the other side, Shroff said San Francisco and other cities were just trying to “avoid accountability” for violating the rights of homeless people, rather than taking steps to reduce homelessness.

“The solution is building affordable housing and making shelter available, which California has been uniquely bad at doing,” Shroff said.

The Supreme Court case is Grants Pass v. Johnson, 23-175.