Ligambi, in a green prison jump suit and white sneakers, said little, but smiled and nodded to more than a dozen relatives and friends who turned out for the hearing.
Jacobs said several were prepared to offer nearly $1 million in property as collateral if bail was set.
He also offered a series of arguments that he said justified bail, including the fact that Ligambi, despite his reputation, has a relatively benign criminal conviction history.
But Assistant U.S. Attorney David Troyer said Ligambi had used the mob's reputation for violence and murder to exert control in the underworld since taking over the top spot in 1999.
Troyer said the government had seven witnesses, surveillance, and secretly recorded conversations to support its contention that Ligambi was a mob boss.
"He is the gatekeeper for La Cosa Nostra," said Troyer, who argued that the organization used its reputation for violence to control sports betting and loan-sharking and, in one instance, to take control of an illegal video-poker operation in South Philadelphia.
Jacobs, on the other hand, said the case against his client and 12 codefendants was "about as squeaky clean as a racketeering case can get," pointing out that there were no murder, attempted-murder, or assault charges - allegations that were all over earlier mob racketeering indictments.
"The government has exaggerated the scope of this case," said Jacobs, who since signing on as Ligambi's attorney three weeks ago has referred repeatedly to the charges as "racketeering lite."
The description of the case is just one of several issues on which the defense and prosecution disagree.
Prosecutors contend that federal sentencing guidelines would call for a sentence range from about seven to 10 years if Ligambi is convicted.
Jacobs said his calculations put the range at three to five years.
Robreno's decision means Ligambi, who will turn 72 in August, will probably spend the next year in the Federal Detention Center at Seventh and Arch Streets awaiting trial.
The racketeering case is built around allegations of loan-sharking, extortion, and illegal gambling.
Six of the 12 other defendants, including several identified as ranking members of Ligambi's alleged organization, have also been denied bail.
Ligambi's criminal history includes convictions in the 1970s for selling untaxed cigarettes and a conviction in 1987 for running a mob-linked bookmaking operation.
A murder conviction from 1989 was overturned on appeal, and in 1997, after serving more than 10 years in prison, Ligambi was acquitted after a retrial.
Despite that acquittal, Troyer argued, in underworld circles Ligambi's "reputation is that of . . . somebody who is a murderer."
Contact staff writer George Anastasia at 856-779-3846 or ganastasia@phillynews.com.
