Which of the following is not a principle of jus ad bellum (just recourse to war)?

In Just War Theory, jus ad bellum (the conditions under which states may justly resort to war) comprises just cause, legitimate authority, right intention, probability of success, last resort, and macro-proportionality. ‘Humanity’ (alongside distinction and military necessity) is a core principle of international humanitarian law and jus in bello (just conduct within war).