[T]eachers have a greater impact on student learning than any other school-based factor. Second, we will not produce excellent schools without eliminating laws and practices that guarantee teachers-regardless of their performance-jobs for life,” Timothy Knowles writes in today’s Wall Street Journal. Knowles, who spend more than two decades in the classroom, is director of the University of Chicago Urban Education Institute.

As somebody who cites quite a few truly excellent teachers among the great gifts of life, I couldn’t agree more. So, like most people, I’ve been angered and dismayed by stories about lousy teachers who can’t be fired. They actually impede the education of young people. Knowles cites a horror story of a napping tenured teacher. Then he offers a fresh and rather startling observation about how the no-firing rule affects schools: 

It’s not news that students suffer when very low-performing teachers are allowed to remain in the classroom. But teachers suffer too. In a forthcoming article, my colleague Sara Ray Stoelinga of the University of Chicago Urban Education Institute illustrates how teacher tenure creates perverse practices in schools across Chicago. In interviews with 40 principals, 37 admitted to using some type of harassing supervision-cajoling, pressuring or threatening-to get teachers to leave in order to circumvent the byzantine removal process mandated by the union contract. One principal plotted to remove a teacher who had trouble climbing stairs by assigning her to a fourth-floor classroom. Another reassigned a teacher who had been teaching eighth-graders for 14 years to a first-grade classroom.

This pathological status quo feeds upon itself: The more difficult it is for principals to address underperformance, the more likely they are to use informal methods to do so. This fuels labor’s argument that management is capricious, strengthening their case for increased employment protection.

This cycle leads to what educators call “the dance of the lemons”-the practice of shuffling underperforming teachers from school to school. It’s easier to push a teacher to a school down the street than it is to push them out of the profession.

The occasion of Knowles article is Colorado’s groundbreaking new law, recently signed by Gov. Bill Ritter, that reforms the tenure system in that state. The law has elicited shrieks of horror from many in the teaching profession. But now other states may be on the verge of enacting similar laws. This is good news. Any child who is willing to learn deserves a teacher who is willing–and able–to teach.