WASHINGTON -- Former Canadian press baron Conrad Black won a significant, but incomplete legal victory Thursday when the United States Supreme Court vacated an appeals court ruling that upheld his 2007 convictions on defrauding Hollinger International Inc.

In a decision that could affect dozens of other white-collar crime cases in the United States, the high court found flaws in the controversial “honest services” statute used to prosecute Mr. Black on charges of mail fraud. His case has been remanded back to the Chicago-based 7th Circuit Court of Appeals to be reconsidered.

“He knows of the news and is quite elated by it,” Miguel Estrada, Mr. Black’s Washington-based lawyer, said in an interview. “We are coming to the end of a long and painful period.”

Mr. Estrada said he will seek bail for Mr. Black, who is serving a six-and-a-half-year sentence in a Florida prison, within the next few days.

The ruling in Mr. Black’s case came in tandem with a separate, but related, decision in the fraud case of Jeffrey Skilling, the former chief of failed energy giant Enron Corp.

The Supreme Court set aside Skilling’s own honest services conviction and placed new limits on a law prosecutors have relied on to pursue American executives accused of corporate malfeasance.

In Mr. Black’s case, the court found that instructions to the jury at his 2007 trial rested on an “improper construction” of a section in federal fraud law which makes it illegal “to deprive another of the intangible right of honest services.”

The 28-word Criminal Code provision was central to Mr. Black’s conviction on three counts of mail fraud for arranging US$6.1-million in payments to himself and his associates from Hollinger International, where he was chairman and CEO.

In its ruling on Skilling, which guided its decision in Mr. Black’s case, the Supreme Court determined that the honest services provision “properly confined, criminalizes only schemes to defraud that involve bribes or kickbacks.”

The Supreme Court said in a footnote to its ruling that the fraud scheme alleged at Mr. Black’s trial did not involve bribes or kickbacks.

The high court said instructions given to the jury at Mr. Black’s trial were “indeed incorrect” and that defence lawyers had the right to raise objections on appeal, overturning the finding by the appeals court.

Mr. Black’s convictions on mail fraud still “technically” stand, said Mr. Estrada, but the Supreme Court’s determination on the limits of the honest services provision throws the jury verdict into question.

“While the jury verdict has not been technically vacated, it has been found to be in error,” Mr. Estrada said.

“The convictions should be tossed ... It is literally impossible for the government to establish that the error [at trial] did not harm Conrad Black.”

Mr. Black had appealed to the Supreme Court jointly with John Boultbee and Mark Kipnis, his ex-colleagues at Chicago-based Hollinger International Inc.

At Mr. Black’s trial, the Supreme Court noted, the jury was told Mr. Black and his co-defendants were guilty of honest services fraud if they misused their positions for private gain and “knowingly and intentionally” breached their duties of loyalty to the company.