Conrad Black arrives at the federal building in Chicago for sentencing on his fraud and obstruction of justice convictions. He received a sentence of 6½ years in prison. (M. Spencer Green/Associated Press)

Conrad Black is taking his fight to the U.S. Supreme Court in a last-ditch appeal that, if successful, could grant him the vindication he has long dreamed of and cast doubt on a controversial law used to trap white-collar criminals.

The former media mogul, who gave up his Canadian citizenship to become a member of the British House of Lords, has been serving a 6½-year term at the federal prison in Coleman, Fla., for fraud and obstruction of justice. He will not be present at the hearing in Washington on Tuesday.

His lawyers have readied an attack that focuses on the right to honest services — a concept developed to convict corrupt politicians who were seen as defrauding the public of their "honest services" as public servants — and whether it should apply to private conduct.

In documents filed ahead of the hearing, lawyers for Black and two co-defendants argue the U.S. government stretched that concept to fit the men's crimes and based it on the evidence of former business partner David Radler, the prosecution's star witness.

The government, for its part, says a proper reading of the law means the convictions must stand, and argue the trial jury was given all the proper instructions relating to honest services fraud.

James Morton, a Toronto criminal lawyer who has followed Black's case, said a win is unlikely, adding he wouldn't put Black's chances above one-third.

"If he wins completely on the honest services issue he's still convicted of obstruction of justice, which, in some sense, you could argue [is] as serious as any of the others," said Morton.

"But I doubt his sentence would have been as long if that's the only thing he's convicted on, so in all likelihood his sentence would be reduced — he might well be released for time served."

Key to freedom?

Neither Black nor his lawyers were available for comment Monday, but they have said the obstruction of justice conviction would be thrown out if the fraud convictions were overturned.

Jacob Frenkel, a former U.S. prosecutor, said he wouldn't have given Black's appeal much of a chance after the scathing opinion from the Court of Appeal. But the fact that the Supreme Court has taken on three cases dealing with honest services may give Black a shot, he said.

"That clearly suggests that it has a problem with the broad application of the law and, for that reason, the defendants in this case could very well benefit from what the court thinks is an over-broad application of the honest services law," said Frenkel.

The hearing is scheduled for one hour — 30 minutes for each side — and will be followed by the case of a former Alaska state legislator convicted of failing to disclose a conflict of interest who is also contesting the honest services provision.

The U.S. Supreme Court agreed to hear Black's case in May and said five months later it would also take up former Enron CEO Jeff Skilling's appeal of his convictions for his role in the collapse of the energy giant on the same grounds.

The issue before the Supreme Court is not whether the facts presented in Black's case were accurate, but rather a broader question of how the law should be applied.

After it hears the case, the top court will have three options: leave the conviction in place, rule that one aspect of the case was flawed, or overturn it entirely. A decision isn't expected until June.

Black's Hollinger empire once controlled a chain of big-city Canadian dailies, the National Post, the London Telegraph and the Jerusalem Post, as well as the Chicago Sun-Times and hundreds of smaller publications.

Black and three other executives were convicted of scheming to pocket about $60 million US in non-compete payments when Hollinger sold newspaper assets. These payments, made in return for promising not to compete in future against the sold-off businesses, should have gone to Hollinger shareholders.