All I can say is... In Ohio, it is acceptable - within limits.
One or two swats on the rear end, with an open hand, in an attempt not to hurt but to get attention, is OK. The intent, though, is hard to prove.
My husband got a protective order against him for swatting my stepdaughter at age 12. Of course, the kids' bio mom swore it was a studded belt (that he did not own), and when she took the child to the ER, there were no marks. Hours later, at the police station, there were fresh marks; they should have been at least 2 days old at that time. Still, the CPO was written. I testified about it - daughter, too (poor kid, BM told her she had to) - and the CPO was vacated. A couple of years later, I witnessed this woman grab Onyxx's arm and yank her over, leaving red marks and later bruising that was verified and documented when I called the police - but they did nothing about it. It was "a reasonable action for a child who was not listening".
FWIW? I'd say don't do it.