Adults at least age 21 have a right to smoke pot in Colorado, but they don’t have a right to their jobs.

So no one should be surprised by the Colorado Court of Appeals ruling Thursday that says state law provides no employment protection for marijuana users. Who said it did?

Adults may smoke marijuana without interference from local or state police. Pot use violates federal law, but the federal government lacks patrol looking for common drug users.

Amendment 64 relieves pot users of prosecution, but that’s about it. The law no more protects a drug user’s job than it protects his marriage and friendships. Drugs use has consequences.

Colorado employment law is clear. This is an at-will state. Employees don’t own jobs, and employers don’t own employees. The two sides work together for mutual benefit. The moment an employee or employer decides the relationship no longer has value, either has the right to end it. It’s a bit like our state’s no-fault divorce law, but far more defensible. Most employees work without contracts. Most marriages are, by definition, contracts of lifelong commitment that are made before family, friends, colleagues and God.

Here’s how the Colorado Department of Labor & Employment explains employee/employer relationships:

“Colorado follows the legal doctrine of ‘employment-at-will’ which provides that in the absence of a contract to the contrary, neither an employer nor an employee is required to give notice or advance notice of termination or resignation. Additionally, neither an employer nor an employee is required to give a reason for the separation from employment.”

Any adult has a legal right to post naughty pictures on blogs or public forums without fear of arrest. The government may not censor us.

But don’t mistake legal protection from government force with employment protection. When we engage in behaviors that violate conventional mores, or are likely to cause offense, we risk harming relationships. A job is nothing more, nothing less than an interpersonal relationship — with the exception of a job that’s protected by contract.

General exceptions to this principle include varieties of discrimination that are specifically prohibited by law. They include firings motivated by an employee’s disability, race, creed, color, sex, age, religion, sexual orientation, national origin or ancestry. If an employer fires a person because she is Catholic or black — and the employee can prove the motivation — the courts won’t allow it.

The case decided Thursday involved plaintiff Brandon Coats, who had worked as a telephone operator for Dish Network. Coats had been paralyzed in a car crash as a teenager and was hired with his disability. He became a medical marijuana patient in 2009. He failed a company drug test in 2010 and was fired on that basis.

A trial court ruled that marijuana use isn’t lawful, because it violates federal law, and sided with Dish.

We contend that marijuana’s legality should have no relevance to the case. If a doctor prescribes a much harder and more debilitating drug — such as morphine or hydromorphone — no one would question its legality. But an employer may decide against employing someone who consumes hard drugs and the employer, in an at-will state, should have a right to end the employee/employer relationship.

While we support the legal philosophy of at-will employer/employee relationships, it’s hard not to feel badly for Coats — a man who was never accused of using marijuana on company property. If he was a good employee, Dish may have discontinued the relationship against the company’s better interests. One could argue that Dish made a morally questionable decision to discontinue a relationship.

Though some may sympathize with Coats, we should all be thankful that our courts respect the at-will nature of employee/employer relationships. No one should employ another person under force of law, any more than one should work for another person under force of law. Freedom requires that interpersonal relationships remain voluntary.