The Supreme Court has sided with former Enron CEO Jeffrey Skilling in limiting the use of a federal fraud law that has been a favorite of white-collar crime prosecutors.

The court said Thursday that the "honest services" law could not be used in convicting Skilling for his role in the collapse of Enron. But Justice Ruth Bader Ginsburg said in her majority opinion that the ruling does not necessarily require Skilling's conviction to be overturned.

During arguments in December and March, several justices seemed inclined to limit prosecutors' use of this law, which critics have said is vague and has been used to make a crime out of mistakes and minor transgressions in the business and political world.

The court, at the same time, rejected Skilling's claim that he did not get a fair trial in Houston because of harshly critical publicity that surrounded the case in Enron's hometown.

The court in this ruling also sided with former newspaper magnate Conrad Black, setting aside a federal appeals court decision that had upheld Black's honest services fraud conviction. But as in Skilling's case, the justices left the ultimate resolution of the case to the appeals court.

The justices also threw out an appeals court ruling against former Alaska legislator Bruce Weyhrauch, who is facing charges under the honest services law.

Thursday's ruling could affect the ongoing prosecution of former Illinois Gov. Rod Blagojevich and the convictions of former Alabama Gov. Don Siegelman and ex-HealthSouth CEO Richard Scrushy.