I live in Massachusetts 
where spanking is still technically legal, with some legislative attempts to outlaw it. Without weighing in on legalities, here are my thoughts on the matter.
For purposes of this post, a “spanking” is an open handed butt smack.
Through an odd set of circumstances we ended up in a house with four kids….two that had been spanked, and two that hadn’t. The two that hadn’t grew up with counting by the parent…one..two..three. Nobody ever knew what would happen if three got reached, but it certainly had to be biblical.
Looking back, while the four children were certainly individuals, there really was little difference in the end behaviors of the kids. Kids were kids, and all needed corrections and reinforcements.
My sense is spankings led to physical pushback and that’s never a good thing. I’ve heard parents justify spanking by saying nothing else really focuses the child, and won’t argue that.
Net net – what is the benefit?
So…having grown up in an environment where a spanking including using a wooden spoon, my recommendation is it is time to take physicality out of child rearing. I’m not into legislating this, just sharing my perspectives. There are far too many better alternatives.