An innovative defense against mail and wire fraud that sprung three former Merrill Lynch executives from prison last year has figured prominently again in a fraud case against a former Enron executive and may end up helping defense strategies for many more white-collar crime suspects.

Christopher Calger, a former vice president at Enron North America, was released from a plea bargain last month and had all criminal charges against him dismissed without prejudice. Calger had pleaded guilty in July 2005 to a charge of conspiracy to commit wire fraud stemming from the sale of Enron assets.