You can justify anything, and people have different reasons for spanking. I have yet to hear of a reasonable justification. I've found that it all comes down to what you want to teach your child.

If you want to teach your child that it's okay to hit others, then this would justify spanking.

If you want to teach your child that there are consequences to bad behavior, then I'd be curious how spanking teaches that.

If you want to teach your child that they have done something wrong, then there are many other alternatives...

For me, spanking creates more problems than it solves. It sets up a power-dynamic (that will disappear when they are teens) and teaches a child to be scared of you. I'd rather raise a thinking child then a fearful one...

Child buttock-battering vs. DISCIPLINE:

Child buttock-battering for the purpose of gaining compliance is nothing more than an inherited bad habit.

Its a good idea for people to take a look at what they are doing, and learn how to DISCIPLINE instead of hit.

I think the reason why television shows like "Supernanny" and "Dr. Phil" are so popular is because that is precisely what many (not all) people are trying to do.

There are several reasons why child buttock-battering isn't a good idea. Here are some good, quick reads recommended by professionals:

Plain Talk About Spanking
by Jordan Riak,

The Sexual Dangers of Spanking Children
by Tom Johnson,

NO VITAL ORGANS THERE, So They Say
by Lesli Taylor M.D. and Adah Maurer Ph.D.

It seems like the majority of child experts say spanking is not justified. According to the NY Times 23 countries have banned hitting kids, however, the U.S. is not one of them. In fact according to the American Academy of Pediatrics, spanking happens at least once a week in 25 percent of two-parent, middle-class families.

When is spanking Justified?
In certain religions, spanking as a form of discipline is justified. An article from Christian Parenting explains when and how spanking is justified. It stresses that the purpose of spanking is "not for parents to express their anxiety or frustration." Instead, spanking illustrates the consequences of crossing boundaries when children rebel or disregard authority. Christian Parenting also explains there should be a balance between enforcing good behavior and showing your children that you love them. For more info: http://www.allaboutparenting.org/spanking-as-a-discipline-for-children-faq.htm

Alternatives to Spankings:
A reason parents might spank their children is because they don't know what else to do, but there are alternative ways to discipline.

• Christian Parent says spanking a temporary solution and lists 10 alternatives to spanking: http://www.christian-parent.com/spanking-alternatives.shtml
• iVillage also lists alternatives to spanking: http://parenting.ivillage.com/tp/tpbehavior/0,,njb0-1,00.html

Reasons Not to Spank
Now, I personally don't think spanking is justified. So I found some reasons not to spank.

1. Hitting children teaches them to become hitters themselves.(http://www.naturalchild.com/jan_hunt/tenreasons.html)
2. Spankings can precondition girls to accept violence and boys to rely on it.
3. Emotionally harms the child and the parent. (http://www.religioustolerance.org/spankin14.htm)
4. Linked to higher levels of adult depression, psychiatric problems, and addictions. (http://www.religioustolerance.org/spankin4.htm)

I noticed there wasn't a lot of answers to your question so you might also want to check out these forums:

• Is Spanking Jusified?: http://www.medhelp.org/forums/ChildBehavior/messages/31068.html
• Is Spanking an Acceptable form of Discipline: http://www.opposingviews.com/comments/risk-outweighs-any-benefit

And for more info, see the sources below: