One issue I don't believe has been addressed here is the evolution in the variety and lethality of weaponry in modern military forces used in battle against quite primitive insurgents. It is here that I find the distinction between war and murder can become blurred.
Petraeus, in heading the team that generated the US military's recent counterinsurgency field manual, noted that counterinsurgency is the most labour intensive of all forms of warfare. The government side, if it seeks to win, is obliged to flood the countryside with soldiers to blanket the population with adequate security that wins them to the government side and prevents the insurgents from establishing their own civil, judicial and military order. In other words, this extremely expensive variety of warfare is required to prevent an insurgency from evolving to the next level - civil war. As Petraeus himself has said, in this sort of conflict, heavy firepower is counterproductive.
Assuming these edicts to be true (and they have been borne out by centuries of experience), what are we to make of war fought "on the cheap" as in Afghanistan? By this I mean war we have waged relying heavily on artillery, armour and airstrikes to make good troop level inadequacies and to minimize our own losses even as we realize it will result in excessive civilian casualties and be counterproductive to our aims?
It is axiomatic of Western judicial systems that we are all deemed to intend the logical consequences of our actions provided those outcomes are reasonably foreseeable. In many crimes there is no 'smoking gun' statement to prove intent and so it must be deemed to exist. A gunman, seeking to shoot someone in a crowd, cannot escape liability for murdering bystanders by honestly asserting he never wanted to shoot them. If this same standard was applied to the use of heavy weaponry in civilian areas what would be the conclusion? Commanders might not "want" to cause civilian deaths but if they realize their actions will take those lives, can they claim not to intend them?
We keep hearing a lot of nonsense about "precision guided munitions." Does the fact that you can land your bomb within 10-feet of your target legitimize using a 2,000 pound bomb to take out a valid target standing in the middle of a packed public market? What if it is a mud-walled compound where you can assume innocent women and children are sleeping?
What bearing does it have if you are using these weapons mainly to avoid the massive expense of fielding combat troops or to dodge the likely political consequences of taking infantry casualties? What about "oopsies" where the commander assumes he's attacking an insurgent force and, instead, winds up taking out an entire wedding party?
In the past we have banned 'uncivilized' weaponry such as chemical weapons yet we seem less reticent to use enhanced destruction weaponry today. For example, take the Israeli use of white phosphorus weapons on the UN compound in Gaza. Another example is the use by major powers of air-dropped minefields that lie about ready to claim civilian lives years, even decades, after the conflict has ended. It seems the more robotically we can deploy these weapons the less responsibility we accept for them afterwards.
Few Americans realize it but the Agent Orange their military so liberally sprayed in Vietnam has an effective lifespan of about five centuries and continues to result in thousands of deformed babies every year. The United States, while it has compensated its servicemen who handled the product, rejects accountability for the monstrous disaster it has left in its wake.
I think the moral verdicts in these matters is clear but what of the legal ramifications?