>>64210118
>being attacked by an external threat gives people a common cause to rally around.
Only when your side is winning. And since winning a nuclear war is basically an oxymoron unto itself, it's a moot point. I know you're going to say "Pearl Harbor" but consider this. Imperial Russia, Austro-Hungary, the Ottoman Empire, all three of these countries violently fragmented despite fighting a war that was widely perceived at its beginning as being one for national survival.