I was one of those people that said I would never spank my child. Then I became a parent.
Well, my toddler decided she liked to be "cute" on walks and would run in the street. I did not find this cute at all. I then decided she needed a spanking. You cannot rationalize with a toddler very well. Rather a swat through the diaper than being hit by a car.
I tried to only use spanking if it was a safety issue. There was one time I can remember that she was spanked for defiance. It was down right ugly defiance, not just a simple "no, I won't listen to you".
I always tried to use other means of discipline when I could. BUt, I do believe in spanking for safety issues and when all other means of discipline have be tried without results.
I did find that it worked. She stopped running into the street. She is almost 12 now and is very well behaved. Yes, being pre-teen, she can still have her defiant moments, but other punishments are more effective now. Now it is . . . you can't go out and play with friends or no TV.
I do not think that spanking will be very effective over about 8 - 9 years old. I really do think it depends on the kid though.
My brother was spanked. He was a stinker. But, I was not since I was an angel.
It really needs to be left to the parent to determine if it is an effective punishment for that particular child. If spanking has no effect, then it should not be used. It is a disciplinary tool that should be used wisely and with great care. But, I do think it is a necessary tool to take out of the tool box on ocassion.