As an adult who teaches, I got to choose an open school. Union politics have now barred millions of families from a similar privilege.I don’t blame schools for closing in March. Very little was known about COVID-19 then, so closures seemed the safest decision amid the uncertainty. Neither do I blame schools for a meager showing that semester. My own district threw together online curricula and instructional materials practically overnight. The results were dismal, but it’s the best many could have done given the situation. However, we’ve now had nine months to understand this virus, and all the evidence favors...