Sweden may be said to have had a "weak central government" in most of the 1700s. The King lost political control of much of Germany, Denmark, Poland, Lithuania, Latvia, Estonia, and Norway, and real control of Finland.
A weak Obama Regime could definitely see much of the Southwest lost to Mexico, New England to Socialist Canada, and Texas to a new independence movement. If you think current unemployment is bad, imagine the country cut into pieces by its enemies.
--and you're free to imagine that I imagine it.