The exercise of brute force by militaries, though common, reflects professional incompetency. A well-trained military has an inherent interest in enhancing its operational effectiveness and constraining unnecessary brutality. The law of armed conflict, however, generally ignores the constraining effect of the necessity principle, originally intended to allow only the minimally necessary use of force on the battlefield. Consequently, the prevailing law places the burden of restricting the exercise of brute military force upon humanitarian considerations (and the specific norms derived from them). Humanity alone, however, cannot deliver the goods and substantially reduce war’s hazards. This article challenges the current dichotomy between the two pillars – mistakenly assumed to be polar opposites – of the law of armed conflict: necessity and humanity. It calls for the transformation of the military’s self-imposed professional constraining standards into a revised legal standard of necessity. Though the necessity principle justifies the mere use of lethal force, it should not only facilitate wielding the military sword but also function simultaneously as a shield, protecting combatants and non-combatants alike from excessive brutality. The suggested transformation would bind and restrain the prospective exercisers of excessive force, political and military alike, and restrict the potential damage that might be caused both intentionally (to combatants) and collaterally (to non-combatants). The combined effect of the current changes in war’s pattern and the law of armed conflict, in the military and social thinking of recent decades, and the new strategies available due to the development of new military technologies have all created a new war environment – one that may be ready to leverage the constraining potential of military professionalism into a binding legal standard and norms.