>There simply aren't enough nuclear warheads to kill everyone directly with kinetic force, This assumes nuclear warheads only and not a doomsday device. If Te

>There simply aren't enough nuclear warheads to kill everyone directly with kinetic force, This assumes nuclear warheads only and not a doomsday device. If Teller Ulam scales with additional hydrogen stages needed only, and not fissile ones beyond the primary, then a doomsday device is possible that does kinectic damage to the entire earth, wiping everyone out. A smaller country that can't develop warheads and delivery systems could potentially none-the-less develop a doomsday device, and it may be rational for them to do so if they think they will otherwise be annihilated and they value others much less than themselves like practically every other nation state in history.