Federal prosecutors yesterday made their final pitch before a three-judge panel of the U.S. Court of Appeals to have former state Sen. Vince Fumo resentenced for his 2009 corruption conviction.

In a decision that prompted public outrage in July 2009, U.S. District Judge Ronald Buckwalter sentenced Fumo to 55 months in prison.

During a 40-minute hearing before the appeals panel, the judges focused their questioning on whether Buckwalter had made, as Assistant U.S. Attorney Robert Zauzmer argued, significant "procedural errors, which, if corrected, could point to a longer sentence."

Zauzmer argued that when Buckwalter granted a departure to Fumo from the advisory-guideline range of 121 to 151 months based on his civic and charitable works, he made an "impermissible" legal error, never stated a final guideline range or adequately explained his reasoning for the departure.

Trial judges, as a first step in the sentencing process, are required to determine an applicable guideline range and other factors before reaching a sentence.

At one point, U.S. Appeals Judge Julio Fuentes said: "It sounds like a very fundamental error and would require resentencing."

Fumo's attorney, Samuel Buffone, said that Buckwalter was not required to restate the new guidelines after the departure but only the final sentence.

Buckwalter was on solid legal ground when he sentenced Fumo, Buffone said, and had the right to fashion a sentence that he saw fit.

And, if there was a mistake made, Buffone said, it was a "harmless error."

After a five-month trial that ended in March 2009, jurors found that Fumo, 68, had turned his Senate staff into personal servants, ripped off a couple of nonprofit organizations and tried to obstruct a federal probe.

Prosecutors had alleged in legal briefs that Buckwalter did not explain why he concluded that Fumo's fraud cost taxpayers only $2.4 million when they offered evidence at trial - which the jury agreed with - that the ripoffs amounted to $4 million. (Fraud exceeding $2.5 million exposes a defendant to a potentially longer sentence.)

U.S. Appeals Court Judge Leonard Garth also raised questions about Buckwalter's calculations. "I don't understand how the 55-month sentence was arrived at," he said.

As a general rule, appeals courts give trial judges wide discretion at sentencing, but a recent 3rd Circuit decision could factor into the appellate panel's decision on Fumo.

In March, an appellate panel here upheld an appeal by federal prosecutors and ordered U.S. District Judge Timothy Savage to resentence two defendants involved in a fraud case. The panel found that Savage did not adequately explain his reasoning for giving the two men lenient sentences.

Fuentes said that the panel would decide the case later.

Fumo, who is serving time at a prison in Kentucky, is scheduled to be released on Aug. 26, 2013.