@Overtake; The idea for the vaults (to the public) were that they were shelters from the oncoming nuclear storm. Enclave thinks we're winning the war too easily, China won't nuke, so they drop their own bombs on China, China retaliates with ICBMs, bombers, nuke subs, etc, we claim China bombed first, we retaliate, boom, nuclear apoc.
@WhiteKnight: Yeah, but ultimately, it's about man. And how war never changes. We brought about our destruction, aliens just popping in dropping bombs on us would be, as you said, dumb.
@Faceless Stranger: He's supposed to be Richard "Tricky Dick" Nixon. I wouldn't trust him as far as I could throw him. Hell, he may not even know the real truth. He's the President, but the Enclave represents a secret, shadowy government with a lot of control. I wouldn't be surprised if it's some Super Top-Secret Eyes Only If You Think About It Too Much We Will Fucking Kill You level of classified. Hell, maybe nobody knows. Nobody has to keep the secret if they don't know it exists in the first place. Enclave history books would say that the chinese bombed us out of desperation, we bombed them back or our bombers followed an automatic protocol and bombed them, world went apoc.