It is perhaps paradoxical that the spread of nationalism in modern times has been accompanied by a counter-movement for the establishment of broader units of government, not only internationally, where plans and projects for some form of world government go back to at least the 17th century, but regionally as well. This study is concerned with the local or regional expression of integration, called federalism or federation.Clearly inspired, if not directly and immediately affected, by the example of the United States, the federal movement made headway in the 19th century, but it is largely since the end of the Second World War and the demise of colonialism, that its dimensions have grown. Although its success generally is rather doubtful—there appears to be a kind of empiric rule that the first fifteen are crucial—the retreat, so to speak, from particularism and attempts to advance to geographically broader units of government have persisted.