Federal governments often extend their powers and usurp local authority, especially if one or more federal units are disproportionately powerful.  The proposition arguments repeatedly rely on the federal state being limited in strength enough to allow local differences and choices. However, historically, federal states have moved to extend their control from the centre often with the justification of necessity. Both the USA and Russia are examples of this trend.1 In the USA, debates about overstretch of federal control are numerous and time consuming. This argument is especially likely if one or a group of federal units are significantly stronger than the other unit, for example the Kingdom of Prussia in the 1871 German Union. In this case, Prussia was able to use its financial strength and size to eventually dominate the Union and control the other federal units.2 1 Garratt , Thomas and Rhine, Russell. 'On the Size and Growth of Government.' Federal Reserve Bank of St. Louis Review. 88 (1). 2006. World Savvy, 2008, 'Centralization of Power in Modern Russia,' 2 Houseofnames.com, 'German Unification,'