In overturning an impaired driving conviction, the 9th U.S. Circuit Court of Appeals ruled Monday that a loophole in Idaho law means marijuana users can drive legally as long as they don't drive erratically and can pass a field sobriety test.

A three-judge panel of the San Francisco-based court wrote that Idaho's impaired driving law makes it illegal to drive under the influence of alcohol and narcotics. But Idaho doesn't list marijuana as a narcotic.

This means when Matthew Patzer, who wasn't driving erratically and passed a field sobriety test, but was arrested for driving impaired after admitting to marijuana use, was arrested unlawfully. The subsequent search of his car, therefore, was also illegal, and so the four illegal homemade grenades, sawed-off shotgun and modified rifle with a homemade silencer they found cannot be used in court for a weapons charge. Of course, this says nothing about what Idaho's narcotics laws ought to say, it's just a morbidly amusing consequence.