How harmful is corporal punishment for children?

In an ideal world, everything would be simple: you, who are the father or mother, tell your child, the apple of your eye, to do something and they, being so obedient and submissive, do as they’re told. We don’t know if such a world would really be ideal. Nevertheless, for many parents, this resembles a paradise where they would love to escape to for at least a few weeks.