TORONTO - The former district attorney who put Conrad Black behind bars for cheating shareholders said Thursday that prosecutors are highly likely to oppose the disgraced media mogul's request to U.S. President George W. Bush to commute his sentence.

Now in private practice, Eric Sussman told The Canadian Press that the prosecuting office in Chicago where Black was tried believes, if anything, he got off lightly with a 6 1/2-year prison term.

"The Chicago office spent the time and the resources in this case because they believed . . . that Mr. Black's conduct was criminal and he deserved to go to prison for it for at least the length of time that he was sentenced," Sussman said.

"I'm not aware of anything that happened in the last six or eight months that would have changed that view on behalf of the attorney's office or for that matter the Dept. of Justice."

Black, 64, was convicted last year of a $6.1-million fraud and obstruction of justice related to his eight-year spell as head of Hollinger International Inc., from which he was fired in 2003.

An internal probe found he and other executives got more than $32 million in unauthorized payments.

He is currently serving his sentence in Florida following an unsuccessful appeal.

In Washington, a spokeswoman for the Office of the Pardon Attorney, which is part of the U.S. Justice Dept., confirmed Black had requested leniency rather than an outright presidential pardon.

"He's requested commutation of sentence," said Laura Sweeney.

However, she said she could not comment on details of the request, which was filed Nov. 10.

As president, Bush has the prerogative to pardon convicted felons -- essentially wipe out the conviction -- or commute their sentences, usually after seeking input from the Dept. of Justice and local prosecutors.

He is under no obligation to go along with either a positive or negative recommendation.

In one highly controversial example, Bush commuted the 30-month prison sentence handed to his former aide Lewis (Scooter) Libby, who was convicted of perjury and obstruction of justice last year for lying to a grand jury about a White House leak.

Experts, however, called the Libby situation unusual given his close ties to Bush, and rated Black's chances of success minimal, particularly in light of the financial meltdown in the U.S.

"Black is just not worth it to Bush," said Peter Henning, a professor of law at Wayne State University Law School in Detroit.

"I don't see that there's all that much appeal for granting a pardon or commutation to a CEO who abused his position, especially in this current climate."

Sussman agreed the administration would have little, if any, sympathy for Black and called his sentence "relatively light" when compared with other CEOs who were convicted of similar conduct.

For example, Jeff Skilling, the former CEO of Enron Corp., was convicted of felony charges relating to the once giant company's collapse and sentenced to more than 24 years.

"I don't think there's a lot of sympathy for well-paid chief executives who are stealing money from shareholders," Sussman said.

"I would be very surprised if there is anyone in this administration that feels that there is anything about Mr. Black's case that would warrant his sentence being commuted."

Rick Powers, associate dean at the Rotman School of Management in Toronto, said Black was "grasping at straws" and rated his chances of success as "infinitesimal" given that he has little connection to Bush or the Republican party.

Black has written biographies of former U.S. presidents Franklin Delano Roosevelt and Richard Nixon.

"If writing about dead presidents is perceived as a good thing, then maybe he has a chance," Powers said.