You might be misinterpreting the term. "Discipline" does not automatically imply corporal punishment, and nobody said it did. It has gotten harder to expel a thug from a school than to fire a civil service bureaucrat. The phrase in the original article, "Expulsion is no longer an option" pretty much says it all.

Teachers nowadays can't kick a kid out of class, can't lay hands on the kid, even in a reasonable manner (grabbing him and hustling him out of the room.) What options do they have?

When I was going to school, if you crossed a teacher the whole damn school, most of the parents, and probably the mayor would be down on your neck. Teachers were supported by the administration in discipline issues.

This was a small-town midwestern school, and I'm fully aware that this was far from an inner-city situation. But we had our share of thugs, too. They just weren't allowed to be in control.