Updated

CHICAGO -- Imprisoned former Illinois Gov. George Ryan is seeking to have elements of his conviction thrown out based on a U.S. Supreme Court ruling that sharply curtailed an anti-fraud law employed by prosecutors nationwide to convict politicians and executives.

The Illinois Republican becomes the latest public figure to challenge convictions based on the disputed provision, joining former newspaper magnate Conrad Black and the former CEO of disgraced energy giant Enron, Jeffrey Skilling.

The hope, Ryan attorney Jim Thompson said Wednesday, is that the move will result in the 76-year-old's release soon from a federal prison in Terre Haute, Ind. Ryan is serving a 6 1/2-year sentence and was expected to be released only in 2013.

In a filing with the U.S. District Court in Chicago late on Tuesday, Ryan's attorneys cited the Supreme Court's June decision focusing on Skilling's case. The justices voted to keep the so-called honest services law in force, even as they joined unanimously in weakening it.

Six attorneys spent months poring through the high court's ruling before deciding to ask federal Judge Rebecca Pallmeyer -- who presided over Ryan's 2006 trial -- to toss the convictions, said Thompson, himself a former Illinois governor.

"Skilling applies here. There claimed that when state investigators from the office of the Secretary of State's inspector general began to look into the payoffs and the campaign fund, Ryan had his aides dismantle the inspector general's office.

Ryan also used state employees and taxpayer money to operate his campaigns while steering lucrative state contracts to cronies who showered him with gifts, prosecutors claimed. Ryan's attorneys maintained that he had violated no laws.

The honest-services ruling also came up at the recent trial of Ryan's successor as governor.

Defense attorneys for former Democratic Gov. Rod Blagojevich cited it in their bid for a mistrial. But Judge James Zagel rejected that, saying the court's decision had no major impact on Blagojevich's case.

Blagojevich's trial ended last month with a conviction on just one out of 24 counts -- lying to the FBI. He is expected to be retried on the remaining charges early next year. He is appealing the one conviction and has pleaded not guilty to the other counts, including scheming to sell or trade President Barack Obama's old Senate seat and to racketeering.

Randall Samborn, a spokesman for the U.S. attorney's office, said prosecutors would not comment on the Ryan filing. He added that no date has been set for a hearing on the matter.