I agree that children should be spoken to at times, yet, if they do not listen, the child should be spanked. A child left alone with only words will not begin to feel scared or worried about the next time they mess up. The strongest memories have a feeling connected to them. Even I, a full grown adult, look back at the times I messed up when spanking was involved. I remember the pain and hurt involved and I do not do the deed again.
If a parents hits a child, it is likely that the child will just get even more angry. Also, what is that teaching the child??? We look up to parents to give us an example of how our behaviour should be, and if our parents are going round smacking us, how are we supposed to know it is wrong? When I was little I was expelled from nursery school by smacking another child who hit me just like my mum did, but I didn't know it was bad because in my little two year old mind, I was just copying my mum. Hitting is damaging, physically and mentally, and should be stopped. Period.
I believe parents are entitled to use spanking as it as an effective form of discipline. There is a big difference between spanking and abuse. Spanking can be used to get the attention of a child with regards to particularly bad behaviors. Children want to avoid that punishment and are less inclined to repeat the negative behaviors. That said, parents who abuse their child (ie by using whips and belts) should get into trouble.
Physical punishment is ineffective because if overwhelms the misdeed. When children (and even adults) look back on a severe punishment, often they remember the pain and fear far more vividly than they recall what they did to make someone mad. Smacking or spanking does not show a child how to do better, or build a sense of proper behavior. All it does is frighten and hurt a cowering child.