So the principles of warfare are: Do not depend on the enemy not coming, but depend on our readiness against him. Do not depend on the enemy not attacking, but depend on our position that cannot be attacked.
As they were during the Cold War, urban population centers remain the most likely targets of a nuclear attack. Now, however, an attack may come without warning from an unknown enemy, to achieve unclear motives.
However desperate the situation and circumstances, don't despair. When there is everything to fear, be unafraid. When surrounded by dangers, fear none of them. When without resources, depend on resourcefulness. When surprised, take the enemy by surprise.
Your enemy shall ye seek; your war shall ye wage, and for the sake of your thoughts! And if your thoughts succumb, your uprightness shall still shout triumph thereby!