There are many possible ways it could go. A nuclear conflict could devastate some parts of the world while leaving others virtually untouched.
Might that explain America's swift recovery vs. ECON's post-atomic horror in the 2070s (building the Conestoga, Valiant
and Friendship One
vs. Encounter at Farpoint
)? It always made me wonder.
Heck, thinking in modern terms, it might be fought mainly using suitcase nukes smuggled in by suicide bombers, rather than by spreads of missiles flying between continents.
Like the TV series Jericho
depicted it, I'd imagine.