Spare the rod and spoil the child

I think that there is a difference between physical abuse and physical discipline as well. But, I think that the line can be crossed easily. I stopped spanking my children and noticed that their behavior was no different. I can discipline them wihtout it so, why do it and risk crossing the line?

If "no" doesn't work, then you throw in a punishment. I taught special ed for a year, and plenty of those kids would throw tantrums and put up a hell of a lot of resistence. If you remove rewards as a result of bad behavior, then behavior will eventually be shaped in a positive manner. The problem is that if you give in even once, then you will lose a lot of influence with the child. Many of those kids' problems stemmed from their parents giving them whatever they wanted, whenever they wanted.
I've learned from personal experience that good children do not need to be spanked and spanking doesn't stop the bad behavoir in bad kids.

So, all it really is a way for an angry parent to spend some energy.

I have raised my kids to understand that physical lashing out is never acceptable. What kind of message would I be giving them if I hit them?