A very intelligent, well-acted, high production film. Anyone who says otherwise really didn't understand it. It's a "what if" with a lose-lose proposition - what if a nuclear weapon is launched on a major US city, and no matter what you do, someone's going to die (like the trolley problem). Even if the nuclear warhead is a dud, the very act of launching one by an unknown enemy, doesn't preclude a second or tertiary launch or a preemptive response by other nations fearful of US retaliation. You make a move and the rest of the world follows - or if they panic - they launch first and ask questions later. Except with this kind of escalation there are no winners. Like Crimson Tide or The Hunt for Red October, the players are in the dark. Like the submarines, they are moving in unknown waters, fearful of an unseen enemy, yet equipped to start WWIII. The ending doesn't matter - it's purposefully concealed - because the characters don't know what the ending is, until it's too late - and neither does the audience. A powerful and moving and ultimately an anti-war film.