MONTGOMERY, Alabama -- Former Gov. Don Siegelman today asked the U.S. Supreme Court to review his 2006 conviction in a government corruption case arguing that there was insufficient evidence to convict him of bribery.

The petition was filed with the high court today, according to Siegelman lawyer Sam Heldman.

"By granting review, this court would have the opportunity to right an injustice, to exonerate a man who has committed no crime, and to clarify the law in a manner that will be important to all candidates, elected officials, and politically engaged citizens," Siegelman's lawyers wrote in the petition.

A federal jury in 2006 convicted Siegelman and HealthSouth founder Richard Scrushy of federal funds bribery on accusations that Siegelman sold a seat on a hospital regulatory board to Scrushy for $500,000 in donations to Siegelman's 1999 lottery campaign.

A key question before the court, Siegelman's lawyers wrote is what is the legal line between campaign contribution and bribe.

Siegelman's lawyers wrote that there was no evidence that Siegelman and Scrushy struck an "explicit quid pro quo" deal to swap the money for the donation.

His lawyers wrote that, at best, the trial testimony of aides only showed that the governor "wanted" the contribution and perhaps Scrushy "wanted' back on the board.

"In other words, there is certainly no evidence beyond a reasonable doubt that Governor Siegelman actually promised Scrushy, or overtly stated to or agreed with him, that an appointment to the (Certificate of Need) Board would be given in exchange for contribution to the lottery campaign," Siegelman's lawyers wrote.

Allowing such "shaky proof" could lead to a troubling number of prosecutions, Siegelman's lawyers wrote, and it is important for politicians, donors and citizens to have a clear line between illegal and legal activity.

Siegelman is also asking the court to review his convictions for honest services fraud and obstruction of justice.