A U.S. Supreme Court decision that has rattled the nation’s teachers union leaders won’t have an immediate effect on New York City teachers.

United Federation of Teachers President Michael Mulgrew said in a statement on Monday that while he “deplored” the ruling, which gives some public workers the ability to opt out of paying union dues, it might only affect Illinois, the state where the case was based.

“Given its specific nature, we are reviewing whether it has any substantial applicability to New York state or city,” said Mulgrew, noting it was “narrowly drawn to a particular situation.”

The ruling upholds “fair share arrangements,” which allow public unions in 20 states, including New York, to require all workers to pay membership fees, regardless of whether they want to be members. The “fair share” money covers contract negotiations and other labor costs and is equal for all members so that no one can unfairly reap collectively-bargained job benefits and protections.

The case, Harris v. Quinn, was brought by a group of Illinois home-care aides who said they shouldn’t have to pay those fees because they often disagreed with their union’s negotiating positions. They sought to overturn a “fair share arrangement” that had been codified into state law.

But the 5-4 decision has still been widely panned by union leaders because it carves out an exception for the aides as “partial-public employees” whose work is not as much in the public interest as teachers and police officers.

While noting that the decision protects more fundamental collective bargaining rights, they also said it represented another effort to weaken unions and, as a result, harm the nation’s shrinking middle class.

“This court has built a record of weakening the rights of both voters and working families; no one should be surprised by this decision,” said American Federation of Teachers President Randi Weingarten in a statement.

Dennis  Van Roekel, president of the National Education Association, the nation’s largest teachers union, defended the “fair share” practice.

“Fair share simply makes sure that all educators share the cost of negotiations for benefits that all educators enjoy, regardless of whether they are association members,” Van Roekel said.