Do any Christian versions of 'Just War Theory' address cases in which foes exploit the principles of Just War to their own advantage? The ends justify the means.  - attributed (perhaps unjustly) to Niccolo Machiavelli


Christian proponents of Just War Theory would surely reject the quote above as being entirely antithetical to their doctrine, but are no doubt committed to 'doing something'* in response to the spread of evil. With these things in mind, how do they formulate an appropriate response to a foe that does not share their inhibitions in terms of means used?  For example in asymmetrical warfare, insurgents who utilize terror tactics will often be aware of the principles that their enemy operates under and will exploit them for maximum effect - utilizing human shields, booby-trapping corpses, or using children to carry explosives etc. - what are the relevant principles that ensure that a Just War can continue to be prosecuted both justly and effectively in the face of tactics such as these and not sacrifice one at the expense of the other? Which, if any, scripture references are used to support these principles?

edit: I believe many of the down-votes to this question are a result of misunderstanding the intent of the question. I apologize for any lack of clarity about this and have edited the title in response to feedback to hopefully make the intent of the question clearer. Further clarification of what I am trying to acheive with this question can be gained by considering the counterpart question (linked below) addressed to Christian Pacifists. Further description of who this question is addressed to can be found in the 'Chrisitan Proponents' linked Q &amp; A.



*This is a reference to the quote of Edmund Burke in the counterpart question to this one:


  The only thing necessary for the triumph of evil is for good men to do nothing.
Summary: No, the Just War doctrine is not intended to provide guidance at this level of detail.

First a brief summary of what the Just War Doctrine is. It's intended to be an answer to the question of whether a Christian can morally fight in a war, and the very brief summary is: "A Christian can fight in a war, as long as it is 'Just'". Many Christian groups hold to this view, with the main alternative positions being the Pacifist one, which says that a Christian can never fight in a war, and the one that says that a Christian can and should fight if ordered to do so by a secular authority.

The doctrine also provides some guidelines for when a war is considered 'Just'. There are two main parts to that. The first is when a war may justly be begun - for example it must not be a war of aggression, it must be fought by a legitimate authority, and only if all other means have been exhausted. The second is the conduct of the war: for example it should be a proportionate response to the evil the war is intended to prevent, and it should involve only what is militarily necessary to achieve its objectives. 

The first rules for a Just War were set out many hundreds of years ago, including those of Thomas Aquinas (1225-1274) and  Stanisław of Skarbimierz (1360-1431). While there have been variants on these rules, the approach has always been to set out principles rather than to prescribe detailed responses to specific situtions. The principles has been applied to wars from the bow-and-arrow era to that of nuclear weapons.

Because of the level at which they are laid down, it makes little sense to try and address specific situations that have arisen only in the last few decades. It is also worth mentioning that none of the forumlators of the Just War guidelines intended them to be applied only in cases in which the other side also 'played by the rules', and it's widely believed that "do good to other people only when they are being good to you" is foreign to Christian belief. Medieval warfare, the norm when these rules were being set down, was at least as nasty as modern 'asymmetric' warfare.