I should have been clearer.
Physical punishment only works in the early stages. Once they can 'argue' back, it becomes a mental game and physical punishment doesn't really improve behavior.
What DOES improve behavior is being CONSISTENT in PUNISHMENT for the DEED.
Parents who keep telling a child "NO" and let the child continue repeating the behavior, and then get so mad they resort to physical punishment, are abusing their child in TWO WAYS, and never solve the problem.
Spanking doesn’t work ever, even when kids are little. What does work is clear rules and consistent consequences coupled with positive reinforcement of good behaviors with redirection as required. I think we agree wholly on the latter part.