Federal law says marijuana is illegal. Some states are now legalizing its use, which leads to some very trouble questions – including what to expect law enforcement officers to do in states where it is legal.

“There’s just an incredible amount of gray right now” about how marijuana legalization affects employers, said Sandra Hagen Solin of the Northern Colorado Legislative Alliance, a coalition of chambers of commerce.

Police departments are especially worried. Officers take oaths to protect all laws, state and federal. In this case, pot is still prohibited under federal law.

The Seattle police department is reviewing its policies on drug use by officers or prospective officers, spokesman Sgt. Sean Whitcomb said, adding that it’s unlikely off-duty officers will be allowed to use pot. The department might ease its requirement that applicants not have used marijuana in the previous three years.