It&#x27;s still a fight worth fighting.<p>Multi-layer defense works. Yes, yes, it sucks when a city gets nuked, but things go way worse if you just give up on the problem and thus allow 1000 cities to get nuked. Think of it like computer network defense. You don&#x27;t just give up because there is a chance of failure.<p>You start with treaties, export control, diplomacy, and a threat to respond in kind. Next it&#x27;s sabotage, both physical and cyber. Next it&#x27;s launch-phase attack... and if they move their launch sites to a less-desirable location to avoid your attack, it&#x27;s still a partial win. Next it&#x27;s an attack right before engine cut-out, possibly from orbit. Next it&#x27;s an attack on the warheads in space; those balloons sure are vulnerable to lasers. Next it&#x27;s an attack right after reentry. Next is building codes, bomb shelters, and emergency services.<p>Every layer has value, even if imperfect. It&#x27;s negligent to leave out even one layer.