<< it is completely possible to raise healthy children without violence >>
Violence yes, but a good swat on the ass is needed now and then. Nothing gets a kids attention like a nice case of the red ass now and then. Tell me, which is more of a deterrent sitting a kid down for a timeout or a belt across the pooper?
in the short term, probably the latter. however that doesn't make it a better punishment.
good resource
It is ineffective: Spanking a child will stop the child from misbehaving for the moment, but studies have shown that the child's compliance will only last for a short time; corporal punishment actually increases the child's non-compliant behavior in the future.
It trains a child to use violence: Spanking can teach children that it is acceptable for the strong to use force against the weak -- the concept "Might makes right" is regularly reinforced. They have an increased likelihood of becoming more aggressive towards their siblings, their fellow students, and (later in life) against their spouses and their own children. Violence as a way of behaving is a learned response.
Spanking creates fear in the child: "The message a toddler gets from a slap or spanking is that a parent or other loved and trusted adult is prepared to induce pain and even do physical harm to force unquestioning obedience. That's terrifying to a little kid...However well-intentioned, a slap registers as the shattering of the whole deal between parent and child. Young children are left awash in feelings of fear, shame, rage, hostility, self-destructiveness and betrayal that they can't yet resolve or manage."