WASHINGTON >> America’s union leaders are about to find out if they were right to fiercely oppose Neil Gorsuch’s nomination to the Supreme Court as a pivotal, potentially devastating vote against organized labor.

The newest justice holds the deciding vote in a case to be argued Feb. 26 that could affect the financial viability of unions that are major supporters of Democratic candidates and causes. The unions represent more than 5 million government workers in 24 states and the District of Columbia who could be affected by the outcome. The other eight justices split 4 to 4 when the issue was last at the court in 2016.

The court is being asked to jettison a 41-year-old ruling that allows states to require government employees who don’t want to be union members to pay for their share of activities the union undertakes on behalf of all workers, not just its members. These so-called fair share fees cover the costs of collective bargaining and grievance procedures to deal with workplace complaints.

Employees who don’t join the union do not have to pay for the unions’ political activities.

Conservative anti-union interests are backing an Illinois government employee who says that being forced to pay anything at all violates his First Amendment speech rights.

“I’m not against unions,” said the employee, 65-year-old Mark Janus, who is represented by American Federation of State, County and Municipal Employees Council 31. “I don’t oppose the right of workers to organize. But the right to say no to unions is just as important as the right to say yes.” He said he opposes his union’s fight for wage and benefit increases when the state is “in pretty terrible financial condition right now.”

William Messenger, the National Right to Work Legal Defense Foundation lawyer who is representing Janus at the Supreme Court, said everything the union does, including its bargaining with the state, is political and employees should not be forced to pay for it.

The issue might have been settled in Janus’ favor two years ago. In January 2016, the court heard an identical complaint from California teachers and appeared to be ready to decide that states have no right to compel workers to pay money to unions.

But less than a month later, Justice Antonin Scalia died and the court soon after announced its tie, in effect a win for the unions. The one-sentence opinion did not identify how each justice voted, but the court appeared split between its conservatives and liberals, the same breakdown seen in two other recent cases about public sector unions.

Those unions cheered President Barack Obama’s Supreme Court nomination of Judge Merrick Garland to fill the court’s vacancy. But the Senate took no action on Garland’s nomination, President Donald Trump won the election and the union opponents rushed new cases to the court to challenge the union fee arrangement.

Union sentiment about Gorsuch was unvarnished when he was nominated and confirmed. “In Neil Gorsuch, Trump has nominated an extremist judge intent on overturning basic, well-established Supreme Court precedents,” American Federation of Teachers president Randi Weingarten said.

Following Gorsuch’s Senate hearing, the Service Employees International Union said, “Throughout the last three days of testimony, Judge Gorsuch has again proved that he isn’t the kind of judge who gives working people a fair shot at justice.”

Having won an unexpected reprieve in 2016 and with Gorsuch on the bench, labor leaders are predictably fatalistic about where this case is headed, focusing on how they might adapt to a world without compulsory payments.

Union leaders have described the years-long fight against fair share fees as a political attack launched by wealthy special interests that want to destroy the labor movement

Their fear is that a ruling for Janus that frees employees from supporting the unions financially will cause union members to stop paying dues, too.

“Are you going to lose some people?” asked Lee Saunders, president of the American Federation of State, County and Municipal Employees. “Sure. I’m not going to lie to you.”

Three Nobel Prize-winning economists and 33 other scholars described the potential fallout as a classic free-rider problem.

“If individuals are not required to contribute, many who undisputedly benefit will nevertheless withhold their contributions out of simple self-interest, and others will withhold their contributions to avoid being taken advantage of by the free riders,” the academics wrote in a Supreme Court filing in support of the unions.

But Saunders, Weingarten and other union presidents said their focus has been on reconnecting with members, who have been more engaged since Trump’s election.

“The opportunity here is to re-engage in a way that the reason for unions in the first place becomes a prominent reason again,” Weingarten said.