San Francisco police can’t be sued for shooting a knife-wielding, mentally ill woman in her room at a group home, the U.S. Supreme Court ruled Monday.

The 6-2 ruling said San Francisco police Sgt. Kimberly Reynolds and Officer Kathrine Holder did not violate the rights of Teresa Sheehan, who survived the 2008 shooting and is suing the city for damages. The decision comes amid an ongoing national debate, after fatal shootings involving officers in Missouri, South Carolina and elsewhere, as to whether police are too quick to use lethal force.

“Considering the specific situation confronting Reynolds and Holder, they had sufficient reason to believe that their conduct was justified,” Justice Samuel Alito said in the majority opinion.

The high court did not address whether officers should have provided Sheehan with “accommodations” or taken special precautions under the Americans with Disabilities Act because of her mental disability, saying that was a matter for the lower courts to decide. Ben Nisenbaum, an attorney for Sheehan, said his client can “finally get her full day in court” and sue the city under the disability act.

“I’m not surprised that the majority opinion granted qualified immunity to the officers,” said John Burris, another of Sheehan’s attorneys. “I do think that the issue still remains as to whether the city can itself be liable for violating the ADA.”

A social worker summoned police to a Mission District group home in August 2008, saying Sheehan, a 56-year-old resident who suffered from schizophrenia, had a knife and had threatened to kill him.

Reynolds and Holder later told investigators that Sheehan had come at them with a knife after they had entered her room.

The officers left and called for backup, but re-entered before help arrived, breaking down the door when Sheehan tried to block it. The officers explained later that they forced their way in, fearing Sheehan might have access to other weapons or escape from the room.

They tried to subdue her with pepper spray, then shot her five or six times when she refused again to drop the knife, the officers said.

Sheehan needed two hip-replacement operations because of her wounds, her lawyer said. Prosecutors charged her with assault, but the case was dropped after a jury deadlocked.

Her damage suit accused police of using excessive force and violating her rights as a disabled person. U.S. District Judge Charles Breyer dismissed the suit, but the Ninth U.S. Circuit Court of Appeals in San Francisco reinstated it in February 2014, saying a jury could find the officers’ second entry and subsequent use of force unjustified.

Breyer’s brother, Justice Stephen Breyer, recused himself from Monday’s decision.

Justices Antonin Scalia and Elena Kagan wrote that they would have dismissed the case entirely.

Scalia criticized lawyers for the city for what he called “bait-and-switch tactics” by “snookering” justices into granting review of the case. The city, in pressing the high court to take the case last fall, had argued that the disability act did not apply when police are facing armed and dangerous suspects. But “imagine our surprise,” Scalia wrote, when the city’s briefs and oral argument in March had “nary a word to say about that subject.”

The Supreme Court took up the case primarily to decide how the disability act applies to police encounters with the mentally ill. San Francisco, joined by other cities and counties and police organizations, had argued that the disabilities act, which requires government agencies to make allowances for physical and mental impairments in their practices, doesn’t apply to armed suspects whom police consider to be dangerous.

The Obama administration largely sided with San Francisco, arguing that police are justified in using force unless they know a person poses no threat to the public.

The case is San Francisco vs. Sheehan, 13-1412.

Chronicle staff writer

Bob Egelko contributed

to this report.

Henry K. Lee is a San Francisco Chronicle staff writer. E-mail: hlee@sfchronicle.com Twitter: @henryklee