The idea of states’ rights is what opened the door to marijuana legalization around the country. But here’s the thing about states’ rights for both employees and employers: You better know exactly what those rights are in the state where you live.

That’s especially important for marijuana users who want to hold on to their current job.

Cannabis is now legal for medical use in 33 states. Doctors can, and do, prescribe it to patients for issues such as chronic pain. But all that is meaningless in many states when it comes to the relationship between you and your employer. Depending on where you live, you can still get fired for using legal medical marijuana.