WASHINGTON >> When patients in South Dakota seek help for serious but manageable disabilities such as severe diabetes, blindness or mental illness, the answer is often the same: With few alternatives available, they end up in nursing homes or long-term care facilities, whether they need such care or not.

In a scathing rebuke of the state’s health care system, the Justice Department said Monday that thousands of patients were being held unnecessarily in sterile, highly restrictive group homes. That is discrimination, it said, making South Dakota the latest target of a federal effort to protect the civil rights of people with disabilities and mental illnesses, outlined in a Supreme Court decision 17 years ago.

The Obama administration has opened more than 50 such investigations and reached settlements with eight states. One investigation, into Florida’s treatment of children with disabilities, ended in a lawsuit over policies that placed those children in nursing homes. With its report Monday, the Justice Department signaled that it might also sue South Dakota.

While the administration has received widespread attention for investigating police abuses and supporting the rights of gay and transgender people, the Justice Department has also steadily made these cases part of its civil rights agenda. The government says that those efforts have allowed more than 53,000 Americans with disabilities to leave institutions or avoid them altogether. It is a small number compared with the 250,000 working-age people who are estimated to be needlessly living in nursing homes, but advocates say the federal campaign has had significant effects.

“There has been as much of a revolution in enforcing disability rights since 2009 as there has been for any other group in the county,” said Talley Wells, a disability lawyer with the Atlanta Legal Aid Society.

There are more than 1.7 million nursing beds in the United States, and many Americans require round-the-clock care and the protection of a nursing home. But for untold numbers of others — with mental illnesses, developmental disabilities or chronic diseases — the confines of a nursing home can be unnecessarily isolating. Yet when patients seek help paying for long-term care, states often steer them toward nursing homes, even though it may not be needed.

One 45-year-old South Dakota man with diabetes told Justice Department investigators that he wished he could be at home with his wife and daughter, but was in a nursing home because he needed help moving around his house on one leg.

A 73-year-old man in a wheelchair told investigators he was in a nursing home against his will. “Some of these places are warehouses,” he said, according to the report.

With help, the Justice Department said, such people could live at home, hold jobs and lead productive lives. Instead, they are confined and segregated from society. Many cannot leave the grounds of their institutions without supervision or perform tasks such as shopping for groceries or cooking meals. One resident told investigators that when friends visited to take him for a car ride, “they have to sign me out, like a kid.”

“These are real issues that more and more people are going to be confronting with our graying population,” said Vanita Gupta, the Justice Department’s top civil rights lawyer.

The Justice Department’s efforts are rooted in a 1999 Supreme Court decision, Olmstead v. L.C. The court ruled that, unless a nursing home is medically necessary, people have a right under the Americans With Disabilities Act to receive care without being segregated from society. Advocates for the disabled have compared that ruling to Brown v. Board of Education, which declared racial segregation in schools unconstitutional. As was the case after that decision, however, change was not immediate.

President George W. Bush issued an executive order in 2001 telling the federal government to work with states to meet the Supreme Court’s decree. During his administration, the Justice Department brought several cases over the living conditions in public nursing homes.

Under President Barack Obama, the department changed its strategy. Rather than focusing on living conditions, the authorities asked whether residents should be confined in the first place.

Since then, officials have created a new body of civil rights law. Rhode Island agreed to end a decades-old system that had kept people with developmental disabilities segregated in adult day programs and to help them find jobs, rather than confining them to low-paying workshops. Oregon did the same last year. The Justice Department has filed documents on behalf of children with mental illnesses in West Virginia and people with developmental disabilities in Indiana.

States have been trying for years to increase in-home care, which is often cheaper than putting someone in a nursing home. “What we’re seeing now is the feds’ involvement, and the courts’,” said Debra Miller, director of health policy for the Council of State Governments. “States are all looking to move in this direction. It’s just a question of how fast you can go.”

Dennis Daugaard, South Dakota’s governor, said his state had made progress but that, with such a sparse population, it faced problems not shared by more urban areas.

“Ideally, we want elderly residents and people with disabilities to be able to stay in their communities and receive the services they need without going to a nursing home,” Daugaard said in a statement. “That can be a challenge for a state like ours, which is made up of rural communities.”

The Justice Department, however, said South Dakota was not trying hard enough to address a problem it has known about for years. In 2013, it spent $133 million in Medicaid money on nursing homes and $27 million on in-home care, the department said.

In-home health aides can be less expensive than nursing homes because they do not provide unnecessary services. States, though, face a chicken-or-egg conundrum. Does money go to nursing homes because beds are often more readily available than in-home services? Or are there fewer in-home services because less Medicaid money is spent on them? And nursing homes have little financial incentive to encourage patients to seek in-home care, Miller said.

Wells, the Atlanta lawyer, said the legal fight was both shaping public opinion and reflecting it. A few years ago, when the Justice Department began aggressively taking on state governments, “you could just feel this movement,” he said. He added that patients deserved options that allowed them to remain part of society.

“It’s what all of us would want for our family members,” he said. “When we need that level of service, do we want that in our homes or do we want that in an institution?”

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