(FORTUNE Magazine) – DEAR ANNIE: Please settle an argument for me. I have a team of six people reporting to me, one of whom is so obnoxious--rude, sarcastic, hostile, and argumentative--that no one can stand working with him. Technically, he is very good at his job, but his attitude is a drag on morale and productivity. I want to fire him, but a colleague of mine says the human resources people won't allow it, because firing someone due to a bad attitude would open us up to a lawsuit. Is this true? FED UP IN FLORIDA

DEAR FED UP: No, it isn't--with certain important exceptions. The first thing to bear in mind is that "employment at will" is the governing principle of employment law in 49 states (all but Montana), meaning that anyone can be fired at any time for any reason at all, or for no reason. "Employees--and bosses--need to understand that the courts give employers extraordinary leeway in deciding whom to fire," says Thomas A. Schweich, an attorney at Bryan Cave in St. Louis and author of a fascinating book, Protect Yourself from Business Lawsuits...And Lawyers Like Me (Scribner, $24). "Failing to get along with co-workers, to the point where morale and productivity suffer, is grounds for firing--because dealing effectively with people is every bit as much a part of your job as the more technical aspects."

A few exceptions to employment at will, although I doubt any of them applies in your case: Whistle blowers are protected, as are people with employment contracts that spell out under what conditions they may be dismissed, and of course civil-rights laws prevent you from firing anybody because you don't like the color of his or her skin or what sex she or he happens to be. What may have your colleague a little confused is a set of guidelines that the federal Equal Employment Opportunity Commission put out in 1997, which in essence extended the protections of the Americans with Disabilities Act to cover people with mental illnesses. One example would be someone who was clinically depressed--hence lethargic, apathetic, and unable to concentrate on work (three common symptoms of depression)--who consequently gets fired for having a "bad attitude." Over the past two years EEOC complaints arising from mental illness have skyrocketed, to 15% of the total last year--making this the single largest category of complaints. So, explains William Walsh, who teaches a course for the American Management Association called "How to Legally Fire Employees with Attitude Problems": "It's important to pinpoint what you mean by 'attitude.' If the problem comes from anything that could be classified as a disability, firing the person could be actionable." Partly for this reason, employers try hard to get people with serious attitude problems into counseling, usually through the corporate employee-assistance program. Even if the company ends up letting the miscreant go, at least it can show in court that some effort was made to help. "Besides," says Walsh, "with the unemployment rate so low, and talent so hard to replace, companies figure that even a troublesome person is a bird in the hand."

Maybe your guy could benefit from some counseling too. It can't hurt to sit him down and suggest it--especially if you make it clear that his future employment depends on his changing his ways.

DEAR ANNIE: I am in my mid-20s and work as the only project developer at a small software company, responsible for total project management and training. I've just accepted a new job that doesn't start until the end of next month. At that point I'll be right in the middle of a big project here. How much notice should I give my boss that I am leaving? Is the standard two weeks enough? SCORPIO

DEAR SCORPIO: Are you kidding? As soon as you finish reading this, get up and go into your boss' office, close the door, and tell him that he'd better start looking for somebody to replace you. It's always wise to make as graceful and considerate an exit as possible, unless you enjoy the smell of smoke from burning bridges. As Marshall Loeb, a former managing editor of this magazine, used to say, "It's a long career and a small community." You have lots of working years ahead of you, and it would be a shame to start cultivating enemies so early.