"This is the place, sisters and brothers, where we make a stand today", said American Federation of State, County and Municipal Employees president Lee Saunders, whose union is the defendant in the case before the court.
Napolitano predicted the unions will lose by a close 5-4 vote and believes Justice Neil Gorsuch will be the deciding vote.
At the core of the Janus case is whether the $45 monthly fee he contributes to his union that goes toward contract negotiations involving salary and other benefits for government employees is inherently political.
Janus' attorney said those fees violate free-speech rights because he often disagrees with union action. Labor unions active in the public sector are already scrambling to deal with the expected result of the case.
Recently, Local 371 of District Council 37 has circulated a flyer about the U.S. Supreme Court Case, Janus v. AFSCME.
If the court rules for the plaintiffs in Janus, state and local government employees in the 22 states that are not right-to-work jurisdictions will no longer be forced to subsidize unions as a condition of their employment. That case ended in a 4-4 draw after Justice Antonin Scalia's sudden death left the Court with an even number of conservative and liberal members.
But the elevation of conservative Neil Gorsuch to the court by President Donald Trump past year is likely to prove a decisive factor this time around.
The case, known in legal circles as Janus v. AFSCME, involves a child support specialist for the state of IL named Mark Janus who is challenging a requirement that forced him to pay fees that were created to cover the cost of the union representing him.
"If people don't have to pay anything, we're going to end up underfunding our unions, and eventually they'll be crippled by it". The justices said then that while teachers and other public employees may not be forced to pay for the union's political activity, they may be required to pay a lesser fee to cover the union's core expenses.
Public arguments in the case of Janus vs. AFSCME begin on Monday. "Those rights are now at risk of being taken away", the Tarrs resident said Monday at a rally of about 60 union members and supporters in front of the Westmoreland County Courthouse.
Mark Janus, an IL government employee, is suing the union that represents him - but of which he is not a member - on the grounds that deductions from his paycheck go to fund activities for views he may not share.
Ohio Federation of Teachers President Melissa Cropper doesn't mince words when it comes to the latest U.S. Supreme Court case.
The Supreme Court is likely to hand down a decision in June.
He is also a fair-share participant, meaning he is not a full union member. With Pennsylvania not being a right to work state - meaning workers covered by a union can refuse to join while paying the fees - SEIU want to keep that status to promote a workforce that provides a sustainable living. "I am confident that they will side with free speech for the people of our great nation", Rauner said of the justices, following the arguments.