New research indicates that spanking has minimal effects on children’s development, explaining less than 1% of behavioral outcomes. The study suggests that controlled, limited spanking may be effective for some young children, especially when used alongside milder discipline methods.
I don’t think the paper is disputing the harm of abusively beating the shit out of your kids.
I think kindenough is making a point about how things can change easily. Its easy to go from “I am punishing my kid” to abuse in a split second and you may not know the difference especial if you don’t/can’t reflect on what happened. A small change over time will go unnoticed. I big change can go unnoticed if you are not watching.