QuoteLike the FSoA, I can see China breaking up into regional fiefdoms.

Breaking along political lines in the FSOA is next to impossible.  All communications are controlled and this prevents the growth of any new movements.  What is happening here right now makes that case.  If something like a Trump takes over, that does NOT count as a revolution.  All that would be is a change of ownership.

Some sort of breakup along administrative lines would fragment the country when one district does something the management of another district does not like.  But to get to an administration phase, martial law must be declared to set up administrative districts.

Martial Law => Administrative districts => Breakup => New kingdoms.

Then the average Joe will be able to die for king and country. 

Then the history of medieval Europe becomes contemporary American history.  Eventually complete with horses serfs, royalty, and the right of first night.

All this is happening while population is dying to medieval population densities.