The firefighter's union had supported Rudy during both of his campaigns for Mayor.
From the NYT archives:
A NATION CHALLENGED: THE FIREFIGHTERS; Second Union Leader Is Charged With Trespassing in Demonstration at Ground ZeroBoth Giuliani and Bernie Kerik took a hardline stance against the firemen, until public pressure forced them to back down.
November 5, 2001
The president of the union representing New York City's fire officers was charged with criminal trespass yesterday, a day after the leader of the city firefighters' union was arrested on the same charge. The police said both allegations stemmed from their roles in a firefighters' protest rally at the World Trade Center disaster site on Friday.
[T]he two labor officials insisted that they had broken no laws in leading the rally. They denounced their arrests as politically motivated tactics dictated by Mayor Rudolph W. Giuliani in an increasingly bitter dispute over scaling back the number of recovery workers at ground zero.
Kevin E. Gallagher, president of the 9,000-member Uniformed Firefighters Association, also blamed the mayor after his arrest Saturday night. "The message the city is sending is that if you don't agree with what a union says, you simply arrest its president," Tom Butler, Mr. Gallagher's spokesman, said.
The arrest of two municipal union leaders was extraordinary. Union leaders have been arrested before -- notably Michael J. Quill, head of the transport workers, for calling an illegal transit strike in 1966. But criminal or civil actions against city union officials have nearly always arisen in the context of corruption or major labor confrontations.
The weekend arrests, however, came in a dispute over the size of the work force at ground zero, and after Friday's emotional protest by firefighters who contend that the cutbacks would turn the recovery of comrades' remains into a "scoop and dump" operation.
During Friday's demonstration, 12 firefighters were arrested on felony and misdemeanor charges, and five police officers were slightly injured in a brief scuffle. The charges were dropped or reduced on Saturday, and while anger lingered in firehouses, tempers seemed to cool as union leaders voiced regret over the scuffling.
"The mayor fails to realize that New York City is not a dictatorship, where if you don't like what a union is doing you can just go and lock up a union's president," the firefighters' union said. "The message being sent from City Hall is that if you don't agree with this administration, we will get you."
Captain Gorman, a firefighter for 28 years, called his arrest an outrage. "They're putting me through the system like I'm a thug," he said. He called the mayor a "fascist" and referred to Mr. Kerik and Mr. Von Essen as "Giuliani's goons."
Steven Rabinowitz, a lawyer for the fire officers association, said that Mr. Gorman had been ordered to report to a station house in Lower Manhattan or face arrest by detectives who would "hunt him down like a fugitive." He said there was no basis for the criminal trespass charge.
Mayor Giuliani was in Phoenix for the World Series.
And on Thursday, the mayor had again lashed out at the firefighters, calling union officials ''sinful'' for questioning the city's motives in making the staffing reductions at ground zero. The officials, who are still unhappy with the number of fire personnel at the site, have said that the change was an attempt to transform an effort to retrieve colleagues who had sacrificed their lives into a ''scoop and dump'' operation.The union remains outraged at Giuliani, today.