Amanda DeSimone-Shabrack relies on a home healthcare aide to help her high-needs autistic 12-year-old son. Virginia’s Medicaid program covers the assistance, enabling her to work as both an education technology specialist and a professor, run errands, and keep Mason in the home.

That could change. In June, the Department of Justice issued a legal opinion saying federal disability rights laws don’t require states to provide services that allow people with disabilities to remain in their homes rather than institutions.

It’s a sharp reversal from 1999, when a landmark Supreme Court ruling held that unjustified institutionalization constituted discrimination under the Americans with Disabilities Act. Previous administrations have relied on that ruling to enforce civil rights for disabled people, but the Trump administration says that long-held interpretation is wrong.

Advocacy groups say legal protections for about 40 million adults and 5 million children who have disabilities could be undermined, and they worry that the new interpretation may herald a return to forced institutionalization.

The stage is also now set for a legal fight between advocates, states, and the federal government. Some states with ongoing lawsuits challenging disability rights requirements are already citing the DOJ opinion in hopes it will help them prevail.