• Under normal circumstances, historic sites and cultural property are protected from military force under International Law.

• If they are used for any military purpose, they lose their protection and are liable to attack.

• However, military efforts must still remain proportional to the intended outcome of an operation.

Proportionality requires that the damage, losses or injury resulting from any military action, not just to one’s own side but considered overall, should not be excessive in relation to the expected military advantage. How can this be squared with pragmatic strategic thinking? After all, in the words of General Eisenhower referring to the destruction of ancient artefacts and cultural heritage: “If we have to choose between destroying a famous building and sacrificing our own men, then our men’s lives count infinitely more and the building must go.” However, Eisenhower didn’t stop there. The quote continues: “But the choice is not always so clear-cut as that. In many cases the monuments can be spared without any detriment to operational needs. Nothing can stand against the argument of military necessity. That is an accepted principle. But the phrase “military necessity” is sometimes used where it would be more truthful to speak of military convenience or even of personal convenience. I do not want it to cloak slackness or indifference.”

Convention for the Protection of Cultural Property in the Event of Armed Conflict with Regulations for the Execution of the Convention 1954

http://portal.unesco.org/en/ev.php-URL_ID=13637&URL_DO=DO_TOPIC&URL_SECTION=201.html

http://www.monumentsmen.com/blog/2013/12/29/3661/3661/