It’s really difficult to fire a bad teacher. A group of Silicon Valley investors wants to change that

Danny Kim:

On a warm day in early June, a Los Angeles County trial-court judge, Rolf M. Treu, pink-cheeked beneath a trim white beard, dropped a bombshell on the American public-school system. Ruling in Vergara v. California, Treu struck down five decades-old California laws governing teacher tenure and other job protections on the grounds that they violate the state’s constitution.

In his 4,000-word decision, he bounded through an unusually short explanation of what was an unprecedented interpretation of the law. Step 1: Tenure and other job protections make it harder to fire teachers and therefore effectively work to keep bad ones in the classroom. Step 2: Bad teachers “substantially undermine” a child’s education. That, Treu wrote, not only “shocks the conscience” but …