The Justice Department released a new legal opinion Thursday that civil rights experts said represents a significant attack against people with mental, physical and intellectual disabilities who receive state-funded services.

The Office of Legal Counsel opinion said states are not actually required by law to integrate mentally disabled patients with their peers by providing community or home-based care, a finding experts say runs counter to long-standing legal precedent and would lead to greater rates of institutionalizing people with disabilities.

The OLC opinion, authored by Principal Deputy Assistant Attorney General Lanora Pettit and posted on the DOJ's website, reinterprets a long-standing Supreme Court case that has served as a cornerstone of America's disability rights law.

That 1999 case, Olmstead v. LC, held that people with disabilities are entitled to receive services in their communities, rather than an institution.

"The Olmstead decision itself said that why community integration is so important is so children can be part of their families, so they can go to school, so people can be part of their communities," said Alison Barkoff, a former DOJ attorney who was in charge of supervising Olmstead civil rights enforcement and now works as a professor at George Washington University's Milken Institute School of Public Health. "That's what's at stake with this re-interpretation of Olmstead."

The Olmstead case was brought by two women with mental and intellectual disabilities who were each repeatedly institutionalized at facilities in Georgia because they could not get coverage for the support they needed to live independently at home.

The Supreme Court held that the state had violated their civil rights under the Americans with Disabilities Act. 

Many in the disability rights community have considered the decision the civil rights equivalent of the famed 1954 Brown v. Board of Education decision, which found that separating children in public schools on the basis of race was unconstitutional.

In its opinion on Thursday, the Justice Department's Office of Legal Counsel suggested that the DOJ's enforcement of the law has gone above and beyond what the Supreme Court intended. 

"Over the past two decades, DOJ's Civil Rights Division ("CRT") has relied on its integration mandate and Olmstead to pressure states into discharging individuals from mental-health institutions," the opinion says. "By threatening or bringing federal enforcement action, CRT has successfully elicited consent decrees, remedial orders, or out-of-court agreements in nearly a dozen states, obligating the participants to meet DOJ's deinstitutionalization benchmarks." 

The opinion added that the Olmstead opinion by the Supreme Court did not in fact impose any integration mandate. Rather, it says, the finding was narrower in scope and held that "unjustified institutional isolation of persons with disabilities is a form of discrimination" under federal law.

CBS News has reached out to the Justice Department for comment on the new OLC opinion.

The OLC's new opinion does not change the law, nor does it serve as any legal precedent. 

But it could fundamentally change the way both the Justice Department and the Department of Health and Human Services enforce allegations of discrimination by patients who received state-funded care.

"For decades, courts have recognized that people with disabilities have the right to live, work, and learn in their communities rather than being unnecessarily segregated from society," said Regan Rush, a former civil rights attorney at the DOJ who now serves as director of a Democracy Forward project called Red Line for Civil Rights. "This opinion does not change the law, but it is a clear warning shot aimed at the legal framework that has protected those rights for decades and at the Department's longstanding role in enforcing it."

The DOJ's new opinion Thursday marks the latest action in a series of efforts by the Trump administration to scale back civil rights protections and upend long-standing missions of the Civil Rights Division.

Earlier this month, the OLC authored another opinion which held that "disparate impact" — a legal theory of discrimination that holds employers liable for discrimination for policies that disproportionately harm protected groups based on race, ethnicity or gender — is unconstitutional.

Harmeet Dhillon, the assistant attorney general for the Civil Rights Division, has also shifted the focus of enforcement efforts away from protecting historically marginalized groups such as people of color and members of the gay, lesbian and transgender communities.

She has launched dozens of investigations into universities over allegations of unlawful race-based admission policies and created a new section within the division that is solely devoted to enforcing Second Amendment gun rights.

Last year, Dhillon angered the disability rights community when she posted a photo of a hat she was knitting online and wrote: "This hat is an hour behind schedule thanks to influencer retards." 

That word is widely considered to be an insulting slur against people with intellectual disabilities.