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.
A commander in chief ought to say to himself several times a day: If the enemy should appear on my front, on my right, on my left, what would I do? And if the question finds him uncertain, he is not well placed, he is not as he should be, and he should remedy it.
Steam was till the other day the devil which we dreaded. Every pot made by any human potter or brazier had a hole in its cover, to let off the enemy, lest he should lift pot and roof and carry the house away.