The criteria of legitimacy are that the atrocities occurring or feared are sufficiently serious to justify, prima facie, a military response; that the response has a primarily humanitarian motive; that no lesser response is likely to be effective in halting or averting the harm; that the proposed response is proportional to the threat; and that the intervention will do more good than harm.
判定合法与否的标准是现实或者担心发生的暴行是否严重到足以采取军事行动；军事行动必须主要出于人道主义动机；非如此可能不足以有效制止或避免暴行的危害；且拟采取的军事行动与威胁成正比；并且干预行动的好处大于它所带来的坏处。