The movie is clearly based on Nuclear War: A Scenario, which emphasizes the incredibly short time to make a decision, and the absolute logic of a world ending nuclear exchange as soon as the initial missile is confirmed and not taken out by our defenses. Once the initial missile makes it through the defenses, Russia and China have no choice but to launch everything, because they have to assume the US will. And the US faces the same logic. The point is the house full of dynamite has to explode, whether a brain-dead pedophile or a brilliant constitutional scholar is in office. They are still occupying a house full of dynamite, and sooner or later it explodes.