The court, in a 6-3 vote, threw out an appeals court ruling that would have allowed a retrial of F. Scott Yeager, a former executive at Enron's failed broadband venture, on charges for which a jury could not reach a verdict at his first trial.
But Justice John Paul Stevens, writing for the majority, did not completely shut the door to another trial.
Yeager sold Enron stock for more than $54 million before the company began a downward spiral that ended in bankruptcy in 2001.
In his first trial in 2005, Yeager faced 125 counts and was acquitted of five, including four counts of wire fraud and one of conspiracy to commit wire and securities fraud. The jury couldn't reach a verdict on the remaining counts, which alleged insider trading and money laundering.
Yeager was later reindicted on 13 counts of insider trading and money laundering.
The issue for the court is whether a variation on the Constitution's guarantee against double jeopardy applies in this situation: The jury votes not guilty on some charges, but fails to reach a verdict on others that are based upon the same essential facts as the charges that resulted in acquittal.
Prosecutors frequently retry defendants when juries can't reach a verdict. They cannot pursue a defendant when juries return not guilty verdicts. This case was about what happens when there is a combination of those elements.
The court said that if the charges all rely on the same basic facts, the defendant's acquittal on some charges "protects him from prosecution for any charge for which that is an essential element."
Thursday's decision reversed a ruling by the 5th U.S. Circuit Court of Appeals in New Orleans. That court said the jury "must have found when it acquitted Yeager that Yeager himself did not have any insider information."
But the government has argued that the jury did not necessarily decide that issue and Stevens said the appeals court could take another look at it, if it wishes. Such a reconsideration could allow Yeager to be tried again.
Justices Samuel Alito, Antonin Scalia and Clarence Thomas dissented.
"There is no clear, unanimous jury finding here," Scalia said, referencing the many counts on which the jury hung.
The case is Yeager v. U.S., 08-67.
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