A federal appeals court [has] issued one of the most comprehensive rulings yet limiting police use of Tasers against low-level offenders who seem to pose little threat and may be mentally ill. In a case out of San Diego County, the 9th U.S. Circuit Court of Appeals criticized an officer who, without warning, shot an emotionally troubled man with a Taser when he was unarmed, yards away, and neither fleeing nor advancing on the officer. Sold as a nonlethal alternative to guns, Tasers deliver an electrical jolt meant to subdue a subject. The stun guns have become a common and increasingly controversial tool used by law enforcement. As lawsuits have proliferated against police and Taser International, which manufactures the weapons, the nation's appellate courts have been trying to define what constitutes appropriate Taser use. Officer McPherson's desire to quickly and decisively end an unusual and tense situation is understandable," Judge Kim McLane Wardlaw wrote for the court. "His chosen method for doing so violated Bryan's constitutional right to be free from excessive force." Some lawyers called it a landmark decision.