Once one of the city's most powerful labor leaders, Joseph Dougherty, the 73-year-old former chief of Ironworkers Local 401, will likely die in prison.

Still, prosecutors have urged a federal judge to add at least seven years to the mandatory minimum 15-year sentence he faces for overseeing his union's sustained campaign of using arson, intimidation, and sabotage to land work for its members.

"The government certainly does not take Dougherty's age or medical condition lightly," Assistant U.S. Attorney Robert J. Livermore wrote in a memo filed in advance of the sentencing, scheduled for Monday.

However, he added, "Dougherty continued to function and run his criminal enterprise even with his advanced age and medical ailments because he had an 'army' of ironworkers willing to do his bidding and commit crimes on behalf of the union."

In fact, just hours after coming out of surgery in 2013, the union president green-lighted an attempted arson at a Malvern construction site at which the builder had resisted calls to hire union ironworkers.

"Somewhere along the way, he began to believe that any criminal act was justified if it furthered the goals of the union," Livermore wrote. "Worse, Dougherty began to expect others in his union to live by his same code."

A federal jury found Dougherty guilty in January of racketeering conspiracy and related counts of vandalism and extortion - the culmination of a months-long investigation that led to the conviction of 11 other union members and the first reshuffling of the local's leadership in decades.

The list of violent acts they carried out reads like a who's who of recent high-profile examples of labor strife.

They include the 2012 arson of a Quaker meetinghouse in Chestnut Hill, the baseball-bat beatings of nonunion workers outside of a King of Prussia Toys R Us store, and an all-out brawl that erupted between union ironworkers and members of the Philadelphia Carpenters union outside of the Convention Center.

Dougherty implicitly encouraged all of these acts, whether or not he ordered them outright, Livermore stressed in his court filings Tuesday.

"Dougherty's attitude toward nonunion labor set the tone for the entire union," he wrote in a recent filing. "Business agents were taught they had to use arsons, extortions and assaults if they wanted to keep their jobs. Union members were taught that they had to commit [those crimes] if they wanted to be hired for jobs or receive promotions."

Pressure to join union "goon squads" and strike back at nonunion contractors only increased as jobs dried up and union membership shrank in the wake of the recent recession, several ironworkers testified at Dougherty's trial.

"Dougherty did not order each and every [violent] episode . . . because he did not have to do so," Livermore said. "The business agents knew their job was to turn around nonunion construction sites by any means necessary. . . . They knew what Dougherty expected them to do."

As Dougherty's lawyer, Mark Cedrone, sees it, that distinction is key to determining a fair punishment for his client.

Because Dougherty was convicted of directly approving only three acts of sabotage - the attempted 2013 arson in Malvern, another that year at a warehouse on Grays Avenue in Southwest Philadelphia, and the extortion of a builder of a small apartment complex at 31st and Spring Garden Streets - he should only be punished for those specific crimes, the lawyer argued in court filings Wednesday.

"It is impossible to discern which of the other acts formed the basis of Mr. Dougherty's conviction" on the government's racketeering conspiracy count, which included all of the violent acts charged against the union's members, Cedrone said.

Cedrone has also urged the court to toss out Dougherty's conviction for the 2013 warehouse fire, arguing that he did not even know the union had purchased an acetylene torch used in the attack.

U.S. District Judge Michael Baylson has yet to rule on that request. Should he grant it, the union leader's mandatory minimum sentence would shrink to five years.

Still, Cedrone said, "we have to live with the jury's verdict."

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