The Natural Law of Self Defense

When individuals or nations are attacked, I believe they have the right to use any means they deem necessary to defend themselves, regardless of man's law. In cases like those, I believe the natural law of self defense trumps any man-made laws.

First, let's look at an example of an individual being attacked. Let's suppose two men get into a verbal argument, and one physically attacks the other. As far as I'm concerned, the man who is attacked has every right to do whatever he feels necessary to prevent himself from being beaten or killed, including shooting or stabbing his attacker, regardless of any laws regarding the use of deadly or unnecessary force.

Now, let's look at an example of a one nation attacking another. When one nation invades another for whatever purpose, right or wrong, by default it gives the regime of the nation it invades a blank check to do whatever it deems necessary to defend itself, regardless of any laws governing war crimes. That nation has a natural right to attempt to drive out, discourage, intimidate, terrorize, or otherwise thwart the invading force. Rules of war shouldn't apply to a country that's being invaded anyway, as the act of starting a war is, by definition, a lawless act.