UNIQUE AMONG education reformers, Gov. Arnold Schwarzenegger has zeroed in on underperforming teachers as a principal reason why millions of California students are doing so poorly in our schools. The initiative he is pushing to make it more difficult for teachers to get "tenure" is a classic case of a solution in search of problem. Let's put aside for the moment the fact that teachers don't actually get tenure. They get "permanent status," which still means under state law they can be fired for all kinds of reasons, including inadequate performance. But they are entitled to a hearing and other...