According to federal surveys, the typical private school’s tuition is only about half what a public school spends per pupil... General Motors would not celebrate the news that its $40,000 Cadillac performed almost as well as a $20,000 Honda. It would not have its dealers put up signs reading: “Why Pay Less? Our Cars Are Nearly As Good.” But that’s the logic of the teachers’ union leaders who want to prevent students from getting vouchers and taxpayers from saving money.