Can a state require a private employer to accommodate an individual who is violating federal criminal law?

Here's a great case about the intersection of state and federal law. (Via How Appealing.) Gary Ross was fired because he failed a drug test, but he was using marijuana medicinally in California, which has legalized the use of medical marijuana. Marijuana is, nevertheless, banned by the federal Controlled Substance Act, and the U.S. Supreme Court made it clear that the states lack the power to carve out exceptions to that act. So Ross was fired for doing something that is a federal crime, but not a state crime.

Ross is suing his employer, Ragingwire Telecommunications Inc., for discriminating against him for his disability, and he's using state anti-discrimination law. So the question before the California Supreme Court — argued yesterday — is the effect of the medical marijuana law. Does the Compassionate Use Act just mean the state can't criminally prosecute medical marijuana users, or does it mean that private employers can't fire them for using marijuana (and violating federal criminal law)?

The state's voters intended to allow medical marijuana users "to fully participate in life regardless of any potential disability," Stewart Katz, a lawyer for Ross, told the court during Tuesday's hourlong hearing in Sacramento. That includes having a job, he said.

But several justices noted that although Prop. 215 protected medical marijuana users and their caregivers from state criminal prosecution, it never mentioned the workplace.

It's a tough state law question. Did the Californians who voted for the initiative that led to the Compassionate Use Act think about much more than the basic mercy of sparing medical users criminal prosecution? Was there any discussion at the time about imposing new duties on private businesses to accommodate drug users?

An employer who hires a medical marijuana user is "arguably being complicit in an activity that's illegal under federal law," RagingWire's lawyer, Robert Pattison, told the court. He said the state law that requires employers to offer reasonable accommodations to the disabled shouldn't be interpreted to require accommodation of illegal drugs.

I wonder whether, if Ross wins in the California Supreme Court, there is a federal question for the U.S. Supreme Court. Can a state require a private employer to accommodate an individual who is violating federal criminal law?