Guilt That Lingers

An Arizona appeals court ruled in February that someone could be found guilty of driving under the influence of marijuana even after its psychoactive ingredient has long left the person’s system. Tests of marijuana measure both active and inactive ingredients — and while the active substance vanishes quickly, the inactive one remains in the body for weeks — so a marijuana consumer might test “positive” even though not the least bit impaired. (In fact, since neighboring Colorado recently legalized some marijuana possession, a Colorado driver motoring through Arizona weeks later could be guilty of DUI for a completely legal, harmless act, as could the 35,000 medical-marijuana users in Arizona.) The appeals court majority reasoned that because the legislature did not distinguish the inactive ingredient from the active, neither would the court.