* Ryan challenged fraud conviction
* Challenge followed 2010 case involving ex-Enron CEO (Adds paragraphs 5-9, case citation, byline)
By Jonathan Stempel
WASHINGTON, Feb 19 (Reuters) - The U.S. Supreme Court on Tuesday refused to hear former Illinois Governor George Ryan's appeal of his conviction and 6 1/2-year prison sentence for racketeering, fraud and other crimes involving kickbacks for state contracts and property leases.
Since his 2005 conviction, Ryan had filed a variety of legal challenges, most recently over the impact of a 2010 Supreme Court decision involving former Enron Corp Chief Executive Jeffrey Skilling.
In that case, the court held that only bribery and kickbacks could be used to show "honest services" fraud.
Ryan contended that this decision meant that the jury instructions in his own earlier trial were faulty, and that prosecutors had failed to prove that he had taken bribes.
In August, the 7th U.S. Circuit Court of Appeals in Chicago rejected his argument, saying there was a "strong sense" that the jury "must have found bribery," and that any error in the jury instructions was harmless.
The 7th Circuit had affirmed Ryan's conviction in 2011, but the Supreme Court asked that it review that ruling in light of the rationale of the Skilling case.
In his Supreme Court appeal, Ryan said the 7th Circuit misinterpreted the Skilling decision, in concluding that a public official like Ryan could engage in honest services bribery if he had no intent at the time to take some official action in return for the benefit.
Gene Schaerr, a lawyer for Ryan, declined to comment.
Ryan, 78, already has served most of his sentence, and is scheduled to be released in July, according to the Federal Bureau of Prisons' website.
The case is Ryan v. U.S., U.S. Supreme Court, No. 12-779. (Reporting by Jonathan Stempel; Editing by Howard Goller)