FORTUNE — Dear Annie: I want to sue my former employer for wrongful termination but, before I go and talk to a lawyer, I thought I’d ask you whether I have a case. My boss, who is an avid marksman and gun collector, already didn’t like me because our politics are so different. (I never discussed politics at work, but I do have a four-year-old Obama sticker on my car.) Then, a couple of weeks ago, I spoke up in favor of tighter gun control laws, during a casual conversation in the break room, and three days later, I was fired. Coincidence? I don’t think so, and several ex-coworkers who have heard this boss badmouthing me don’t think so either.
Doesn’t firing someone because of their political opinions violate their First Amendment rights? If I sue the company for wrongful termination, what are my chances? — Down and Out in Denver
Dear Down: Let’s clear up one common misconception right away. As I’ve mentioned in this space before, when you are at work on private property belonging to an employer, and on company time, you have no First Amendment rights. (Government employees do, but that doesn’t apply here.) “People think political speech should be a protected category under federal law, but it isn’t,” says Sharon Stiller, a partner and director of the employment practice at law firm Abrams, Fensterman.
Four states, however, do have statutes that protect your right to express your political views at the office without fear of reprisal. They are Louisiana, South Carolina, Connecticut, and California, so that doesn’t help you. What your home state of Colorado does have is a law that says an employer can’t penalize you for political activities outside of work — running for office, for instance, or campaigning on someone else’s behalf on your own time. But, since you piped up about gun control in the break room, that doesn’t help you, either.
(By the way, New York and North Dakota also have laws that say your political activities outside of work are your own business. California is the only state that protects political speech both on the job and away from it.)
But there’s a much broader issue here, and that is the widespread confusion over what the term “wrongful termination” means. Many people seem to think that getting fired for any reason that seems unfair or unreasonable is “wrongful.” But in fact, the dominant legal principle in the U.S. is “employment at will,” which means that, unless you’re covered by a union agreement or an employment contract that says otherwise, you can be fired for any reason, or for no reason.
“You can be dismissed for being left-handed, or blue-eyed, or too short, or too tall, or just because the boss doesn’t like you,” says Stiller. The flip-side of employment at will is that (again, absent a contract that dictates something different), you’re free to quit anytime and go to work somewhere else — cold comfort though that may be, in a job market where employers seem to hold all the cards.
So if wrongful doesn’t mean unfair, what does it mean? Federal law spells out a handful of public policy exceptions to employment at will. You can’t legally be let go because of your sex, age, race, or religion, or because you complained about sexual harassment.
In addition, state laws cover some situations that federal law doesn’t address. “Sexual orientation is protected in some states but not others,” notes Stiller. “Other states have created their own protections. New York, for example, has made victims of domestic violence a protected category.” Federal statutes like Sarbanes-Oxley, and many state laws, also protect whistleblowers against reprisals for reporting company wrongdoing to regulatory authorities.
Those who were fired for other reasons probably can’t make a case that his or her dismissal — however knuckleheaded it might have been — was wrongful termination. “The only way for individual employees to protect themselves is by understanding their legal rights before a problem arises, rather than finding out afterwards,” Stiller says.
To illustrate what she means, consider Nelson v. Knight, a case a couple of months ago where the Iowa Supreme Court decided that it was okay for a woman to be fired because she was too attractive. (I’m not making this up.) The facts in a nutshell: After plaintiff Melissa Nelson worked as an assistant to a dentist named James Knight for more than 10 years, he suddenly decided she was “irresistible” and began flirting with her and making suggestive remarks. This upset Knight’s wife, who insisted that Knight fire Nelson. He did. Nelson sued him, claiming sex discrimination, on the grounds that, if she were not female, none of this would have happened.
The court disagreed, saying that firing someone because a consensual relationship has made a third party jealous is not sex discrimination. The point is that “employees do have rights, but they need to know what those rights are,” says Stiller, who thinks Nelson might have won if she had not welcomed her boss’s amorous advances (as apparently she did). “She didn’t have a sex discrimination case, but she might have had a sexual harassment case if she had handled the situation differently.
“Even in big companies with very good legal and HR departments, most front-line managers don’t understand these issues any better than employees do,” Stiller adds. “Employers need to do a better job of educating people about what their rights are and aren’t — and about how to raise issues before they get to the lawsuit stage.” A word to the wise.
Talkback: Does the concept of “employment at will” seem fair to you, or does it overwhelmingly favor employers? Leave a comment below.