In 2006 the Michigan Supreme Court interpreted the state's drugged driving law as prohibiting people with any trace of marijuana metabolites in their bodies from operating a motor vehicle. Since metabolites can be detected in a person's urine weeks after he smokes pot, the decision (PDF) essentially made it illegal for marijuana users to drive, regardless of whether they are under the drug's influence. This week the Court, which shifted to the left after Chief Justice Clifford Taylor was defeated by Diane Marie Hathaway in the 2008 elections, reversed that ruling. The relevant statute says a person may not drive "if the person has in his or her body any amount of a controlled substance listed in schedule 1," which includes marijuana, THC (marijuana's main active ingredient), and their "derivatives." While the 2006 ruling deemed the marijuana metabolite 11-carboxy-THC to be a "derivative," this week's decision (PDF) rejected that reading of the law. "We hold that 11-carboxy-THC is not a schedule 1 controlled substance," the court said, "and, therefore, a person cannot be prosecuted…for operating a motor vehicle with any amount of 11-carboxy-THC in his or her system."
In addition to providing a crucial fourth vote for this position on the seven-member court, the 2008 elections gave Michigan a medical marijuana law. Although that law was intended to protect patients who use marijuana for symptom relief from arrest, the court noted, treating marijuana metabolites as a controlled substance would make them vulnerable to arrest whenever they drive. More generally, it said, a policy of zero tolerance for metabolites has "tremendous potential for arbitrary and discriminatory enforcement," criminalizing behavior based on variable laboratory standards for reporting a positive result and "the whim of police and prosecutors." Given this reality, the court said, "Michigan citizens cannot be sure of what conduct will be deemed criminal."
[via the Drug War Chronicle]