Under Colorado law, employers are forbidden to fire people for "any lawful activity" in which they engage on their own time outside the workplace. Yesterday the Colorado Supreme Court considered the novel question of whether "any lawful activity" includes cannabis consumption that is permitted by state law but still a crime under federal law. Although the case involves medical use, it has broader implications now that Colorado has legalized recreational use as well.

The plaintiff is Brandon Coats, a 34-year-old quadriplegic who was fired from his job with Dish Network in 2010 after he tested positive for nonpsychoactive traces of marijuana. Coats uses cannabis to relieve the seizures and muscle spasms he has suffered since he was injured in a car crash as a teenager. Such cannabis consumption was allowed by state law when he was fired but prohibited by federal law, which is still the case. Dish Network has a "zero tolerance" policy regarding illegal drug use, regardless of whether it affects job performance. Coats argues that state legality is all that's required to make an activity "lawful." His former employer disagrees, and so did the courts that have heard his case so far.

Th Denver Post reports that the justices were "mostly scratching their heads" at yesterday's hearing, and I certainly am no better situated to decide whether a law driven by a desire to protect tobacco smokers should be interpreted to protect pot smokers as well. But I will say this much: The law should never have been passed to begin with. Although I believe that drug policies such as Dish Network's are stupid, I also believe that employers have a right to adopt stupid drug policies (along with any other conditions of employment that people voluntarily accept when they take a job). Such arbitrary rules surely would be much less common in the absence of prohibition—a drug policy that, unlike Dish Network's, is imposed at the point of a gun. But forcing people to hire cannabis consumers is wrong for the same reason that cannabis prohibition is wrong: It posits threats of violence as an appropriate response to choices that violate no one's rights.