The battle over public-sector union dues in the wake of the U.S. Supreme Court’s Janus v. AFSCME decision heated up on Wednesday as the Cuomo Administration and outside groups offered up differing opinions on the importance of membership cards.

The latest dustup started early in the day when a group known as New Choice NY sent out an email blast to more than 500,000 New York public sector employees inviting them to a website that includes a form letter for people who want to leave their unions.

Hours later, Gov. Andrew Cuomo said he ordered the state Department of Labor to issue guidance on complying with Janus. The guidance said: “Public employee unions are not required to produce dues authorizations cards for members from whom the employer has previously deducted dues.”

That drew fire from Ken Girardin, policy analyst for the fiscally conservative Empire Center.

He pointed to state labor law that says union dues should be deducted “upon presentation of dues deduction authorization cards signed by individual employees.”

In June’s Janus decision, the U.S. Supreme Court ruled that public employees who don’t belong to unions no longer need to pay “agency fees” which are akin to dues and are supposed to pay for their unions’ efforts when it comes to collective bargaining and other employment related issues.

It was a long-anticipated decision that was seen as a significant victory for conservatives who dislike public employee unions. The fear among union leadership was that, since non-union members could now stop paying their fees, full members might just leave their unions as well and pocket the dues money.

If enough dues-paying members were to quit, New York’s historically powerful public-sector unions representing employees such as teachers and police as well as state and municipal workers would eventually face financial challenges and consequently lose some of their considerable political clout.

The majority of the approximately 1.2 million public employees in New York belong to unions, although there has always been a small number who pay the agency fees. Those fees are no longer being withheld following the Supreme Court’s decision.

Several public employer groups said they didn’t believe the need to show membership cards for union members would be an issue, since the court decision is aimed specifically at non-member agency fee payers.

“There has not been much discussion of union membership cards by the county employers,” Stephen Acquario, executive director at the State Association of Counties, said in an email.

“The whole Janus decision and what school districts need to do only affects those people who were not full-fledged (union) members,” added Jay Worona, general counsel at the state School Boards Association, whose members employ teachers.

Still, there were inklings that the membership card question could become an issue. The Empire Center in a news release, included a transcript of a recent Saratoga County Board of Supervisors meeting where officials noted that they were the only county statewide so far that was interested in seeing union membership cards from their 625 employees who belonged to the Civil Service Employees Association.

The county payroll department had names of CSEA members but just a handful of their union cards on file.

No matter where the card issue ends up, there seems to be at least some level of curiosity about the situation post-Janus.

Robert Bellafiore, spokesman for New Choice NY,  said the website logged at least 3,000 visits by noon. They had obtained names of public employees and deduced their emails by using the standard conventions for government internet addresses.

He also downplayed the idea that they are pushing people to quit their unions. “We’re not being critical,” he said. “We are just saying that these are your rights.”