Federations collapse from the stupidity of their leaders rather than the bolshevism of their members. The United Kingdom is no exception. It was pieced together in the 18th century from the half of the British Isles that the Normans had failed to conquer and assimilate. It began to disintegrate when the Irish had had enough of inept English government. Now the Scots are reaching the same conclusion, and up to a point the Welsh.
http://www.guardian.co.uk/commentisfree/2011/oct/11/england-first-empire-devo-maxWell. There is at least one more!