One of the posts about putting Nixon up in Alcatraz gave me a funny idea for an ATL...
Nuclear war in mid 70's due to some problem. Most probably, butterflies from locking Nixon up causes the Soviets to believe that the population of the US doesn't trust their government.
So Nixon and his guards, Secret Service and a company of Marines, try to survive as best they can on the Rock.
Refugees arrive by boat seeing that the Rock has a form of civilization on it.
The Reconstruction of California is spearheaded by this group led by, of course Richard Nixon.