Yes, I believe spanking isn't an issue. (If it's not taken to the point of abuse, *in my opinion* there is a difference between spanking and leaving welts / bruises)
Granted I was a pretty well behaved child but I was spanked when I was a kid when I did things wrong and it affected my decisions as a kid.
The issue now, and this is prevalent in a lot of aspects in society, people realize that the punishments are so minuscule that they feel doing the wrong thing is okay, because they can tolerate the punishment.
To me, it's sort of similar to breaking the law. If the punishment is something small, like a small fine, people are more apt to say "Screw it, I'll just pay the fine" and break the law anyway.
BUT if the fine were say, $5000 instead of $25, I guarantee they would think twice about breaking the law, or in this case acting a fool.
I know they're not exactly comparable, but I think it makes sense.
Granted I will never have children because I can't stand them but I can't tell you how many kids I encounter at work that are just downright disrespectful and rude. It's not because they're mad or little asshats, it's because they weren't taught to respect other people. We give away balloons at my work and kids that are wild yank them out of your hand, don't say thank you or just walk up and say "Give me a balloon". You'd better believe I say "Not until you ask nicely" Lol