The Supreme Court on Tuesday is set to hear a dispute regarding union fees that -- while failing to receive substantial media hype -- is poised to have major consequences on organized labor's recruiting.

The justices will review a lawsuit filed by home-based health care workers against Illinois Gov. Pat Quinn over a state statute that requires public-sector employees to pay the portion of union dues that doesn't go to political activities, even if they choose not to be in the union.

The case "maybe is really the sleeper case of the [current Supreme Court] term -- the one that come June we all recognize as probably a landmark" case, said Andrew Grossman, a constitutional law and legal policy expert, and a fellow at the conservative-leaning Heritage Foundation.

"At the very least it's going to have a profound effect on the growth in the future of organized labor in the United States."

The Illinois Human Services Department runs two Medicaid-waiver programs that subsidize home-based services for disabled patients. A patient selects a personal assistant who meets qualifications set by the state, which pays the assistant directly.

Illinois, like many states, considers such workers state employees for collective bargaining purposes, with unionization a condition for their employment by the state.

The Service Employees International Union has represented the assistants for the past decade.

But Pamela Harris, with several other health care workers, challenged the set-up, arguing the workers instead should be characterized as independent contractors and therefore shouldn't be forced to contribute to a union against their will.

The plaintiffs say the Illinois law violates First Amendment free speech rights and the 14th Amendment's Equal Protection Clause, which requires each state to provide equal protection under the law to all people within its jurisdiction.

The case is a major test for laws that require non-union workers to pay a part of usual union dues assessed by a labor organization. The Supreme Court famously tackled the issue in 1977, when it ruled in Abood v. Detroit Board of Education that union shops that are legal in the private sector are also legal in the public sector.

If the high court sides with Harris, it would be a major blow to organized labor, leaving it without a key tool used to recruit and retain members.

The extent of the impact depends on how the court rules. If they rule for Harris, they could say that the contractors are not state employees and therefore shouldn't have to pay dues. Or they could decide that the workers are state employees, but state employees shouldn't be forced to pay union dues if they don't want to belong to the union.

"The state's interest here in maintaining labor peace is, to say the least, somewhat attenuated," Grossman said. "A decision for [Harris] would give millions of state and federal workers [nationwide] the right to choose whether or not to support the union for themselves."

But the SEIU argues that a ruling against the state would threaten the collective-bargaining rights of home care workers.

The American Association of People with Disabilities says an unfavorable ruling for the union could leave Illinois' home-based health care worker system in flux, thus hurting patient care.

"A ruling that declared Illinois' [dues paying] arrangement unconstitutional would disserve individuals with disabilities and undermine efforts to achieve the goals of independent living," said the group in an amicus brief to the high court.

State and federal appeals courts have sided with the state. But with the conservative-leaning Supreme Court having a tenuous relationship with organized labor in recent years, it's uncertain exactly how the justices will handle the case.