Everyone is rightly horrified about the case of a first-grade teacher at a Silver Spring elementary school who was just charged with several counts of assault after being accused of choking and/or punching eight young students. Adults assaulting students at school? That has to be wrong. Right? Wrong, says the Washington Post. This case in Montgomery County Public Schools in Maryland serves as a good reminder about legal whacking, better known as corporal punishment, which is still allowed in 20 states and which is administered to hundreds of thousands of students a year…