This week Tim Stevens, a 53-year-old Amarillo man who smokes marijuana to relieve the cyclical vomiting syndrome associated with HIV infection, used a necessity defense to win an acquittal on a possession charge. His attorney, Jeff Blackburn, says this appears to be the first time the defense, which argues that breaking the law was necessary to prevent a harm worse than the one the law is aimed at preventing, has been successful in a Texas marijuana case.

Stevens, whose vomiting has been so severe that he was hospitalized and received blood transfusions, was arrested last October after an anonymous tipster saw him sharing a joint on a friend's porch in Amarillo and called the police. He had about a twelfth of an ounce of marijuana, resulting in a Class B misdemeanor charge that carries a penalty of up to six months in jail and a $2,000 fine. He probably could have gotten off with a fine or a year's probation, Blackburn says, "but he didn't want to; he wanted to take a stand." The trial lasted about 10 hours on Tuesday, and the jury came back after 11 minutes with a "not guilty" verdict.

Blackburn says the expert testimony of  Steve Jenison, medical director of the Infectious Diseases Bureau in New Mexico's Department of Health, helped establish that marijuana is demonstrably effective at treating nausea and superior in some ways to the legal alternatives. (For one thing, unlike the synthetic THC capsule Marinol, it does not have to be swallowed and kept down, a feat for someone suffering from severe nausea.) Blackburn, who was not at all confident about the prospects for Stevens' unusual defense in a "very, very conservative area," also credits "a streak of independence" and a "distaste for government" that he says is common in West Texas. "I think these jurors like the idea that they get to make a decision about what the law means, about when it applies," he says, "and I don't think they were shy at all about deciding how valuable the law proscribing marijuana use really is."