John A. “Junior” Gotti insists he’s a new man, but a jury will hear prosecutors describe him as a lot like his notorious father, overseeing a violent mob family that enriched itself on the misfortune of others.

The trial beginning today could put Gotti away for 30 years. It will feature the testimony of Gambino family turncoats, evidence from electronic surveillance, and a recounting of crimes including the attempted assassination of a radio personality, Curtis Sliwa.

Mr. Sliwa, who founded the Guardian Angels crime-fighting group, was ambushed June 19, 1992, after he hailed a cab in Manhattan. He recovered, returned to his radio show, and resumed criticizing the Gottis.

Gotti, 40, is charged with conspiracy to kidnap Mr. Sliwa, though charges of conspiracy to murder and aiding and abetting the attempted murder of Mr. Sliwa were dropped by prosecutors a week ago. Other charges include fraud, extortion, and securities fraud. He will be tried with two alleged soldiers in the Gambino family.

Prosecutors have alleged that Gotti wanted Mr. Sliwa attacked because of Mr. Sliwa’s stinging criticism on his radio show of Gotti’s father just before the elder John Gotti was sentenced for a racketeering conviction to life in prison, where he died in 2002.

The government contends that the younger Gotti’s behavior was consistent with its claim that he ran the Gambino organized crime family after his father went away. The defense, in arguments aimed at getting Gotti released on bail a year ago, said he has found a new life far from the mob.

Gotti has been rejuvenated during his last five years in prison after he pleaded guilty to racketeering, using his time to undertake “an ambitious course of self improvement and compiling a near pristine disciplinary record,” his lawyers said.

They noted that government surreptitious recordings of Gotti and his closest confidants had demonstrated a “bitter, disenchanted, and reluctant mafia persona, stripped of power and alienated from the Gambino family administration.”