Thanks, Jorge, for your explanation of the fundamental moral problems with war as presently practiced. I do have a few quibbles, though, and some thoughts to add in agreement to yours.

1. It's a bit of a stretch to say that if action to repel an attack does not involve taxation, harm to innocents, nor disregard for individual rights, then it is not war. I think most people would still consider it to be war if it involved the use of lethal force against the enemy.

2. While you make a valid case that some actions taken by some of those fighting the British during the American Revolution was immoral, it does not therefore follow that the entire war was immoral. Libertarians are the last people in the world who should be making the mistake of treating a diverse collection of individuals as one monolithic, collective entity. The fact that A and B fought the same enemy, and A used immoral means in his fight, does not imply that B also used immoral means.

3. However, your criticism of the American Revolution raises a valid point about the dangers of any sort of prolonged, organized violent action: as men become accustomed to the use of violence, it becomes ever more tempting to use it in ways that are not purely defensive. War tends to be morally corrupting because it transforms violence from a rare expedient used only in extreme situations to ensure immediate survival, into a habitual activity, thereby eroding the normal inhibitions against its use.

4. It is worth noting that the American Revolution did NOT start in 1775, at Lexington and Concord. For a good ten years prior to that time, starting in 1765, the American colonists had been fighting British rule through largely non-violent measures (various sorts of non-cooperation, civil disobedience, boycotts, etc.) By early 1775, British rule was severely weakened; one British official complained that the King's officers had virtually no effective authority in the colonies. What might have happened had the colonists managed to continue resisting through nonviolent means, without submitting to the British?