Wow, I believe I have READ the Old Testament. And I wouldn't want to try to argue that any war this nation has been involved in for at least the past 40 years was in any way self-defensive (because except perhaps Afghanistan they weren't). Nor would I want to stand before God Almighty and argue that killing Chavez was somehow self-defensive either.
I would suggest you go back and reread the entire Bible.
It has occured to me, that when the bible was written, the idea of self-defense, and even war, was pretty much a man-to-man situation. Do you think God meant, by self-defense, that it should only be individuals...or is modern warfare, with carpet-bombing, and lots of collateral damage to civilians, OK with God?