Labor leaders fear the Supreme Court's decision curtailing the ability of public unions to collect dues from workers could strike a blow to their influence in New York.

“This is an attack on unions, which means it's an attack on working people, especially working people who are in unions,” said Mary Sullivan, CSEA vice president.

The leader of the state's largest public workers union, CSEA's Danny Donohue, went even further when criticizing President Donald Trump, underscoring the anger labor leaders feel in the wake of the Janus vs. AFSCME decision.

"If his idea of freedom is, ‘just do what I tell you,’ I know some people named Hitler or Mussolini or Stalin, who he could have mentored, everywhere he goes,” said Donohue.

The ruling prevents public unions from collecting fees from non-unionized workers, driving concerns some union members could simply leave or not join labor organization, but still reap the benefits of collective bargaining.

“We've also prepared for this. It's not a sucker punch. We've been preparing for this fight. We're ready to fight back,” said Andy Pallotta, NYSUT president.

New York has the most unionized private and public workforce in the country — allowing labor to flex its muscle in policy and politics.

“We're seeing an expansion or really the First Amendment rights of folks being restored to them. But really and truly, if the unions are representing the folks fairly well, I don't think there's that much for the unions to worry about in terms of people wanting to flee,” said Lev Ginsburg, director of Government Affairs - Business Council.

Gov. Andrew Cuomo has had a rocky relationship with public labor leaders, but has since made peace with them. On Wednesday, he signed an executive order shielding public employees’ addresses and phone numbers from public view in order to prevent what he said were conservative activist campaigns from persuading workers to leave their unions.

“This is part of a political movement. There are groups that are trying to harass government employees and harass government employees into leaving the union,” said Cuomo.

State lawmakers and Cuomo previously in March approved a provision in the budget softening the expected blow from the Janus ruling, allowing unions to set the terms for when a member could leave.