In a slight glimmer of hope for Conrad Black, a U.S. Supreme Court panel seemed to suggest Tuesday that the so-called honest services law used to prosecute him is too vague.

Miguel Estrada said the so-called honest services law is "amorphous and open-ended."

He noted that the Supreme Court wanted the law clarified in 1987, and the U.S. Congress tried -- but failed -- to do so.

Of the nine-member panel, several appeared to agree with Estrada on Tuesday, including newly appointed Sonia Sotomayor. They fired questions at federal government lawyer Michael Dreeben about the law.

Justice Stephen Breyer suggested the law could apply to someone slacking off at work reading about horse races, noting that it could be argued the employee was depriving his boss of honest services.

"There are 150 million workers in the United States," Breyer told Dreeben. "I think possibly 140 million would flunk your test."

In 2007, Black was convicted of three counts of fraud and one count of obstruction of justice related to $5.5 million in payments he received from a subsidiary of his company, Hollinger International.

He is serving a 6 �-year prison term at Coleman Federal Correctional Complex in Ocala, Florida.

Black was not present at the hearing in Washington.

CTV legal analyst Steven Skurka said Tuesday the law was first developed to prosecute corrupt public officials, but has been used in recent years to charge corporate executives.

Experts argue the law should not apply to conduct within private enterprise.

"It takes questionable ethical conduct and it turns it into criminal conduct," Skurka told Canada AM in an interview from Washington. "And that really is the concern here, that innocent people, who may have engaged in some questionable things, are going to be prosecuted and serve years in jail."

Should he win his appeal, Black's fraud convictions would be thrown out. However, his obstruction of justice conviction, which does not relate to the honest services statute, would still stand.

While he would have to return to Chicago, where his trial was held, to ask that he be re-sentenced on that single charge, Skurka said, Black's lawyers could argue for time served.

"So if he wins in the Supreme Court, does he get rid of all of his convictions? No," Skurka said. "But does it mean he can gain his freedom? It does."

If he loses his appeal, Black will likely serve about six years of his sentence, Skurka said.

Black had applied to be released on bail during his appeal. However, U.S. District Court Judge Amy St. Eve, who presided over Black's Chicago trial, turned down the request.

A decision is not expected until June 2010.

With files from The Associated Press