Bosses, have I got an idea for you: Don’t pay your best employees more, don’t ease out your least productive workers, and for crying out loud, never fire anyone, not even for the most blatant misconduct on the job.

It works for the public schools, doesn’t it?

Actually, it doesn’t, but since they’re government monopolies, they don’t care. They never go out of business. They just keep doing what they’re doing, year after year, churning out class after class of students handicapped by a poor education.

Don’t get me wrong – not all public school teachers are bad. Many are talented and passionate, even heroic. Many turn down better paying jobs because they want to help kids learn. But working hard for public-school students has to be its own reward, because a lazy teacher is paid just as much as a good one – more if he has seniority.

What is the result? When we asked students about their teachers, some said things like this:

“Most of the teachers they’re like – they don’t really care.”

“One of my teachers tells me he does this for the health benefits.”

“I’ve seen teachers come to school intoxicated.”

Joel Klein once won fame as a fighter of monopolies. He worked for the federal government, and his most famous foe was Microsoft. Now he runs a monopoly of his own: the New York City public schools. It’s even more arrogant than Microsoft, because its customers have even less choice.

Joel Klein now presides over a calcified monopoly where it’s hard to fire anyone for anything.

One New York teacher decided that one of his 16-year-old students was hot. So he sat down at a computer and sent a sexual e-mail to Cutee101.

“He admits this,” said Klein. “We had the email.”

“You can’t fire him?”

“It’s almost impossible.”

It’s almost impossible because of the rules in the New York schools’ 200-page contract with their teachers. There are so many rules that principals rarely even try to jump through all the hoops to fire a bad teacher. It took six years of expensive litigation before the teacher who wrote Cutee101 was fired. During those six years, he received more than $300,000 in salary.

“Up, down, around, we’ve paid him,” said the chancellor. “He hasn’t taught, but we’ve had to pay him, because that is what is required under the contract.”

Hundreds of teachers the city calls incompetent, racist, or dangerous have been paid millions.

And what do they do while they get paid? They sit in rubber rooms.

They’re not really made of rubber, of course. They are big, empty rooms where they store the teachers they are afraid to let near the kids. The teachers go there and sit, hang around, read magazines, and waste time. The city pays $20 million a year to house teachers in rubber rooms.

A new union contract is supposed to make it easier to fire teachers for sexual infractions, but the Byzantine rules for other offenses remain. Insane as most are, some teachers told me they support the firing rules. “You prove I’m a bad teacher!” said one. “And if you can’t prove it, don’t try it!”

The restrictions on firing teachers are defended as a means of protecting teachers from favoritism. But if schools and principals had to compete, good teachers would be protected by competition itself: If a principal’s job depends on having good people working for him, he won’t sacrifice it to give a favored incompetent a job he can’t do.

Taking six years to fire a teacher doesn’t do anyone any good – except bad teachers. So why do it? The short answer is unions. The long answer is next week’s column.

Mr. Stossel is co-anchor of ABC News’s “20/20” and the author of “Give Me a Break.”