To some, the Chicago teachers’ strike that ended Tuesday proves what they’ve been saying all along: That the teachers and their unions, when you get right down to it, care more about protecting bad teachers, seniority and pay than they do about what is good for kids.So it’s no surprise that people who hold those views also think the most important reform we should pursue is to use standardized test results to identify our worst teachers. And, of course, they will get behind any measure that will weaken the unions generally.Those people are just plain wrong. Their “reform” agenda has driven our teachers into a bunker — a bunker that teachers have invited their unions to join because they now think the unions are the only friends they have left.No nation has ever fired its way to a top-quality teaching staff.