The Supreme Court will hear arguments about forced unionization among government workers on Tuesday in a case that could greatly curtail powerful labor groups.

At issue is an Illinois law crafted by imprisoned former Gov. Rod Blagojevich (D.) and enforced by his successor Pat Quinn (D.) that forces home healthcare workers, including family members caring for relatives, to pay union dues.

The state claims that the caregivers are government employees since patients receive taxpayer dollars through Medicaid and Medicare. But the issue is more complicated than who is signing the checks, according to lawyers for the National Right to Work Legal Defense Foundation (NRTWLDF), which is spearheading the challenge.

"The Illinois law only defines them as employees in terms of unionization and no other rights at all," said NRTWLDF lawyer Bill Messenger. "This is a scheme for compulsory lobbying."

The caregivers do not receive liability insurance coverage or retirement benefits that other government workers are entitled to, according to Messenger. If the court holds that state governments can force any secondary beneficiary of taxpayer dollars in the union, "vast swaths of the population" would end up paying union dues.

"All doctors or nurses who care for Medicare patients would have to join a union by that logic," Messenger said. "What unions are looking at is trying to attach themselves to any kind of government funding."

Harris v. Quinn could be a defining case in labor law, according to labor experts.

Justin Wilson, managing director of labor watchdog Center for Union Facts, said that forcing healthcare workers to pay union dues has been a cash cow for public sector unions, which enjoy a larger membership than private unions. Michigan unions, for example, benefitted from a similar policy that was eliminated by GOP Gov. Rick Snyder and later rejected by voters in a 2012 ballot initiative.

"Home healthcare workers have been ripe sources for Service Employees International Union, as they represent the largest pool of untapped resources," Wilson said. "There’s real money on the line for the unions."

The case could extend beyond Illinois and home healthcare workers. Messenger is pushing the justices to overturn the 1977 Abood v. Detroit Board of Education, which allowed governments to enforce compulsory union membership as a condition of employment.

If he is successful, public employees across the country could withdraw from their unions in a manner akin to Wisconsin Republican Gov. Scott Walker’s labor reforms.

"Compulsory unionism infringes on the First Amendment rights. The Illinois law and the unionization of providers shows what’s wrong with the Abood decision," Messenger said. "It’s time to bring some measure of freedom to public employees."

Wilson said that the ambitious goals of Messenger and his allies could change the landscape of labor relations for years to come.

"What we’ve recently seen is that public sector workers represent the future of the labor movement because it’s been relatively easy to unionize them," he said. "It could have sweeping ramifications on the future by raising the question of whether compulsory membership is allowed."