One of the key arguments used by opponents of Sue Bradford's Crimes (Substituted Section 59) Amendment Bill is that smacking is not the business of the state. It's an argument seen clearly in Gordon Copeland's speech on the bill's second reading, where he said
The bill as it stands, in my view, is gravely flawed. I say that because of my deep conviction that the right and the responsibility to train and discipline children belongs to parents. The role of the State should be limited to ensuring, for the common good, the safety of New Zealand children. But subject to that overriding criterion, the choice of which particular means parents use to discipline their children belongs to them, and to them alone.
He goes on to say that the bill intrudes into the home, and that "the State does not belong there". Which is exactly what people said in the past against progressive attempts to criminalise domestic violence, child abuse, and spousal rape. They all happen in the home, but the state very definitely does belong there. And the reason is precisely that duty to ensure people's safety Copeland speaks of - a duty which encompasses all New Zealanders, regardless of age. The core duty of the state is to protect people from violence - and "violence" includes smacking. We would not tolerate bullies giving people a "loving smack" on the street to "discipline" them; we do not tolerate people smacking their partners, even when it causes no more than "transitory and trifling" harm. We should not tolerate people smacking their children either. While parents have a right to raise their children how they wish, they have no right to use violence against them.