Freedom, wherever it existed as a tangible reality, has always been spatially limited. This is especially clear for the greatest and most elementary of all negative liberties, the freedom of movement; the borders of national territory or the walls of the city-state comprehended and protected a space in which men could move freely. Treaties and international agreements provide an extension of the territorially bound freedom for citizens outside their own country, but even under these modern conditions the elementary coincidence of freedom and a limited space remains manifest. What is true for freedom of movement is, to a large extent, valid for freedom in general. Freedom in a positive sense is possible only among equals, and equality itself is by no means a universally valid principle but, again, applicable only within limitations and even within spatial limits. If we equate these spaces of freedom—which, following the gist, though not the terminology, of John Adams, we could also call spaces of appearances—with the political realm itself, we shall be inclined to think of them as islands in a sea or as oases in a desert. This image, I believe, is suggested to us not merely by the consistency of a metaphor but by the record of history as well.
Hannah Arendt, On Revolution (New York: Viking, 1963), pg. 279