ALBANY, N.Y. -- Union leaders from AFL-CIO to CSEA are in Albany to rally as the Supreme Court hears arguments from a public worker from Illinois, who is challenging the requirement that he join a union and pay dues.

New York has the highest union membership in the country, even as public and private sector labor enrollment has declined nationally. Unions in New York retain key political influence in both policy and in elections.

On the opposite ideological side is Mark Janus, whose challenge was taken up by the U.S. Supreme Court. It's decision could have wide-ranging impacts on how unions are funded, and according to union leaders, weaken workers' rights.

"I think it is very important for us to keep in mind that this is not just about Mr. Janus. This is about a right-wing, conservative ideological attack on working men and women and in fact, organized labor, the public sector in particular," said Mario Cilento, the AFL-CIO president.