NEW YORK (CBSNewYork/AP) – Unions staged rallies across the country Saturday, ahead of a Supreme Court case that could make it harder for the unions to operate.

Thousands of members attended a Day of Action rally in Manhattan’s Foley Square.

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“This is the place, sisters and brothers, where we make a stand today,” said American Federation of State, County and Municipal Employees president Lee Saunders, whose union is the defendant in the case before the court. 

Starting Monday, the Supreme Court will hear a challenge to an Illinois law that allows government employee unions, such as AFSCME, to collect fees from workers who choose not to join. The unions say the outcome could affect more than 5 million government workers in 24 states and the District of Columbia.

The court split 4-4 the last time it considered the issue in 2016. Justice Neil Gorsuch joined the court in April and has yet to weigh in on union fees. 

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New York City Mayor Bill de Blasio and Gov. Andrew Cuomo, both Democrats, vowed to protect unions regardless of how the Supreme Court rules.

“We will not let our city or our country be taken over by the 1 percent,” said de Blasio. He said New York “is the biggest union town in America and we are proud of that.”

Cuomo said workers “need the strength and solidarity of the labor movement more now than ever.”

He pledged that “as long as I am governor of the state of New York, the state of New York is going to have the back of organized labor.”

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(© Copyright 2018 CBS Broadcasting Inc. All Rights Reserved. The Associated Press contributed to this report.)