Turning young men into lethal combatants, whether in standing militaries, insurgency groups, police forces or violent gangs, or as lone killers, is extremely time- and resource-intensive. It takes months if not years of constant breaking and rupturing of basic human connections; it often requires systematic cruelty and brutality; it requires intense indoctrination; it requires rupturing relationships or having family members or peers who encourage killing rather than discourage it; and it requires the systematic “othering” of the “enemy.” None of these things are hard-wired into us as human beings. Indeed, the research, from Darwin onwards, is overwhelming that we survived and thrived as a species because our biological and social propensity to live in connection and close cooperation with others is vastly stronger than any propensity to kill or harm each other.