The fate of classroom teachers and other public-sector union workers remain uncertain after the Supreme Court heard oral arguments Monday in the Janus v. American Federation of State, County and Municipal Employees (AFSCME) Council 31 case. Mark Janus, a child-support specialist employed by the State of Illinois, claims the current union law violates his First Amendment rights, and the ruling could have wide-ranging effects on the status of unions in the United States.

"If the Supreme Court's decision is based on merit, on facts and on the law, there's no doubt they will rule in favor of working people," AFSCME President Lee Saunders said in a statement.

"The case presents an opportunity for the Supreme Court to give Janus and all government workers — not just in Illinois, but across the country the freedom to choose whether to give their money to a union," according to a statement from the Liberty Justice Center, which represents the social worker along with the National Right to Work Legal Defense Foundation.

At issue is whether public-sector unions should be unable to collect "fair share" (or "agency") fees from workers who are not union members but do nonetheless receive the increased pay, benefits and working conditions that unions bargain for them and the rank-and-file.

"Nonmembers' fair share fees cover the union's expenses related to collective bargaining and contract administration, but not expenses for political or ideological advocacy," according to Celine McNicholas, Zane Mokhiber, and Marni von Wilpert of the Economic Policy Institute in Washington, D.C.

This is not the first time the Supreme Court has heard arguments against public-sector unions’ fair share fees.

"More than 40 years ago, the Supreme Court unanimously affirmed in Abood v. Detroit Board of Education that fair share fees could be collected from public-sector workers," according to McNicholas, Mokhiber and Wilpert

The issue was also brought up two years ago in the case of Friedrichs v. California Teachers Association, whereby 10 public school teachers argued that such an arrangement violated their First Amendment rights. After Justice Antonin Scalia died Feb. 13, 2016, the Supreme Court delivered a split 4-4 decision in the case on March 29, 2016, thereby upholding the constitutionality of Abood v. Detroit Board of Education.

But the fight was not over. The side against fair share fees had breathing room to pursue a follow-up case.

With justices seeming to line up on similar 4-4 votes, it appears that Justice Neil Gorsuch, who President Donald Trump appointed after the death of Scalia, will cast the decisive vote in the Janus case. Gorsuch remained silent throughout oral arguments, asking no questions. However, legal experts think the conservative justice will side with Janus.

If so, the financial blow to teachers unions looms large. USA Today is reporting that union contracts cover 49 percent of preschool through high school teachers — about 2.5 million.