Monday's 5-4 decision left intact the court's 1977 ruling in Abood v. Detroit Board of Education. That ruling said unions could collect such compulsory dues used for non-political activities under collective bargaining agreements.



Illinois law excludes such in-home caregivers from retirement and health insurance plans and the state does not assume liability for actions taken during the course of their employment, Judge Samuel Alito noted.



"Illinois deems personal assistants to be state employees for one purpose only, collective bargaining," Alito wrote.



The National Right to Work Foundation lauded the ruling.



"We applaud these home-care providers' effort to convince the Supreme Court to strike down this constitutionally dubious scheme, thus freeing thousands of home-care providers from unwanted union control," the group's president, Mark Mix, said in a statement.



Harris cares for her adult son Josh Harris, who has a rare genetic syndrome and needs around-the-clock care.



In Illinois, as in many states, home-based personal care workers who assist the disabled are paid with Medicaid funds as state employees. The practice is meant to lower overall care costs by keeping disabled individuals at home and out of institutions.



For more than a decade now, home-based workers in Illinois have been represented by SEIU Healthcare Illinois-Indiana. The collective bargaining agreement between the union and the state provides that all such workers pay compulsory union fees.



Harris, along with other home-based workers, sued Illinois and Governor Pat Quinn, a Democrat, claiming that the compelled payment of union dues was a form of forced speech prohibited by the First Amendment of the U.S. Constitution.



A district court dismissed the case, citing long-standing Supreme Court precedent that mandatory union dues can be collected to support non-political activities. The 7th U.S. Circuit Court of Appeals in Chicago affirmed that ruling after concluding the workers bringing the case were state employees.



The workers asked the Supreme Court to take the case. That prompted the filing of friend-of-the-court briefs supporting the workers from several conservative groups, including the Cato Institute, the Center for Constitutional Jurisprudence and the Illinois Policy Institute.



Labor unions, the American Association of People With Disabilities and the state of California were among interests that filed briefs supporting Illinois in the case.



The case is Pamela Harris, et al v. Pat Quinn, Governor of Illinois, U.S. Supreme Court, No. 11-681.