Is Violence Ever OK?

My kids are 9 & 10. We regularly teach them not to hurt others. We try to teach fairness, openness, and tolerance. But there are times when those approaches break down.

I believe that there are times when violence is not only acceptable, but required, a view that seems extremely unpopular these days. But when might violence be required?
1) When you are afraid for your life.
2) When a bad person attempts to harm an innocent.
3) When the harming of a bad person will save innocents.

When bad people actually act on their threats it changes all of the rules. Talking is a great way to meet verbal threats, but once bad people move to action talking is no longer of much value. You see, I have been held at gun point. And during that very short and uncomfortable time, diplomacy was not an option.

I suspect that most of the liberal politicians that are so against torture (even though they were well aware of it's use ahead of time) would change their tune if their own family and friends were threatened. It seems that a very strong argument for softer tactics is the idea that the threat we face is not really that bad. In fact, the threat we face may be entirely imagined!

But 9/11 says otherwise. Iran says otherwise. North Korea says otherwise. The taliban say otherwise (I won't capitalize their name).

Maybe I'm wrong. Maybe all Iran needs is to be convinced that it's policy of wiping Israel off of the face of the earth is too harsh. Maybe North Korea just wants to be included in global talks. Maybe the taliban, who believe women are second class citizens, just need to be heard.

Then again, maybe they just need to see that such evil will lead to the quick and painful death of their kind. Maybe shooting them is the best diplomacy there is.