The real problem, it seems to me, is the need to determine what degree of force, applied in what manner, against what targets, may states reasonably expect acceptance by the majority of other states.
Miller, William O.
"Belligerency and Limited War,"
Naval War College Review: Vol. 22
, Article 5.
Available at: http://digital-commons.usnwc.edu/nwc-review/vol22/iss1/5