This exchange from a brief interview with the Boston Globe’s Dan McGowan is enough to prove retired teacher Michael Marra’s new book worth reading:

Q: You’re a former schoolteacher who has become disenchanted with public employee unions. Did you start out that way or did something happen to change your mind?

Marra: I didn’t start out that way. But within a year or two, it became apparent that exceptional teachers were being dismissed while clearly less competent, less enthusiastic, less passionate teachers were being retained. Why would any organization, especially one involved in the crucial task of educating our children, mandate contract language that demands a “last hired, first fired” policy?

Seniority and tenure are to blame for this. I’ve watched dozens of high-quality, inspiring teachers with less years in a system receive layoff notices while some blatantly poor-performing teachers were retained. It’s an insult to students, parents, taxpayers, and the teaching profession.

This is one of those truths that, once you see it, you can’t unsee.  An education that — by design! — must fire awe-inspiring teachers and keep substandard ones is on its face doomed to failure over time.

Marra goes on to ask, rhetorically, “Why are unions so afraid to celebrate their best and purge their underperformers?”

Because that’s not their incentive.  The best teachers don’t need unions.  In an independent, free system, they’d be recognized, valued, and in high demand.  They’d be making more money than they are now.  They’d also have a lot more say in how schools are run than they do now.

In any workplace where employees are not basically interchangeable, the employees who most need the protection of a union are the ones who cannot (or do not want to) do excellent work.  Some good teachers will find the security and limited services of a union worth the cost of dues, but in general, the least competent people in a workplace are likely to be the strongest union supporters.

Put differently, teachers unions aren’t selling high-quality education.  That may be one of their talking points, but it isn’t their defining product.  They’re selling job security, and the market for job security it strongest among those who feel insecure.  Incompetence is a leading source of a sense of insecurity.

The public, as well as good teachers, need to understand that dues are not the only cost of unionization.  The elevation of “less competent, less enthusiastic, less passionate teachers” is a cost as well — a huge one.

But that’s not the end of the costs.  In order to protect those teachers while keeping salaries high enough that good-to-excellent teachers don’t feel undervalued, unions had to play in politics so they could control both sides of the negotiating table and manipulate state and federal law to make education more expensive than should be.  That’s a cost across the board, as schools crowd out other things that communities need, like road repairs and public safety, not to mention crowding out private expenditures with taxes.

As they tend to do, the costs continue to compound in unexpected ways.  Having built a powerful political machine, teachers unions began to attract radicals, and they have shifted their organizations’ focus away from their core mission.  At this point, they are simply progressive activist organizations that offer employee services as a way to collect taxpayer money and be intrinsic to government.  The cost of that is existential for our country.