Big Urban centers SOL. Be interesting to see what sort of advances have been made in missile defense.

Hear they have developed electronic means to interrupt nuclear detonation sequences.

More flyover country off the hook with post cold war closure of SAC bases (for me that's Griffiss and Plattsburg).

Nation/State attack would likely start with Cental US EMP followed by higher yield airburst over cities (max casualties, keep the ground from soaking up blast energy).

Terrorist likely ground burst due to limited delivery capability. Poison Earth, lots of fallout.