A federal appeals court on Tuesday upheld the corruption conviction of former Providence, R.I., Mayor Vincent "Buddy" Cianci (search), one of New England's most popular politicians who oversaw a renaissance in his city even as corruption ran rampant in City Hall.

The 2-1 decision by the 1st U.S. Circuit Court of Appeals (search) came 20 months into Cianci's five-year, four-month prison sentence for a single count of racketeering conspiracy.

He was acquitted of more than a dozen other corruption charges — including bribery and extortion — following a sensational seven-week trial in federal court in 2002 that brought an end to one of the most celebrated and controversial reigns in contemporary American politics.

The charismatic Cianci, 63, was cast by prosecutors as the head of an administration infested with corruption at all levels.

The FBI's investigation, code-named "Operation Plunder Dome," relied heavily on corrupt former city officials who cooperated with prosecutors to avoid prison, and their star witness — an air-conditioning contractor who posed undercover as a corrupt businessman to ensnare some of Cianci's closest aides.

That informant, Antonio Freitas, carried a hidden video camera and captured Cianci's top aide, Frank Corrente (search), taking a $1,000 cash bribe. Corrente was convicted of seven counts, including racketeering, in the same trial as Cianci. His conviction and that of politically connected tow-truck operator Richard Autiello were also upheld Tuesday by the appeals court.

Cianci's defense team said the government presented no direct evidence that the mayor took bribes. Prosecutors countered that the mayor insulated himself by using Corrente and other subordinates as his "bag men."

Cianci's defense also argued that the government's case hinged on two former city tax officials — Joseph Pannone and David Ead — who could not be trusted to tell the truth. Pannone was captured on surveillance tapes boasting about how Cianci taught him how to take bribes and get away with it.

Under federal law, participants in a racketeering conspiracy are responsible for the acts of other conspirators.

The longest serving mayor in Providence's history, Cianci was first elected in 1974 as a Republican. He survived an earlier federal corruption probe that ensnared nearly two dozen members of his administration.

He was forced from office in 1984 after pleading no contest to assaulting a man he suspected of having an affair with his estranged wife.

Cianci bounced back and ran for mayor again in 1990, this time as an independent, and reclaimed the office. His second tour in City Hall heralded the advent of the acclaimed "Providence renaissance."

Rivers long diverted through underground culverts were reclaimed, and parks were built along their banks. New attractions sprang up, and $300 million was spent on transportation improvements.

But federal prosecutors say a culture of corruption also took root when Cianci returned to office.

Even after he was indicted in April 2001, he remained highly popular. But he resigned after his sentencing in September 2002 and reported to prison three months later.