Some quotes from Hannah Arendt
“While isolation concerns only the political realm of life, loneliness concerns human life as a whole. Totalitarian government, like all tyrannies, certainly could not exist without destroying the public realm of life, that is, without destroying, by isolating men, their political capacities. But totalitarian domination as a form of government is new in that it is not content with this isolation and destroys private life as well. It bases itself on loneliness, on the experience of not belonging to the world at all, which is among the most radical and desperate experiences of man."
“Terror can rule absolutely only over men who are isolated against each other… Therefore, one of the primary concerns of all tyrannical government is to bring this isolation about. Isolation may be the beginning of terror; it certainly is its most fertile ground; it always is its result. This isolation is, as it were, pretotalitarian; its hallmark is impotence insofar as power always comes from men acting together…; isolated men are powerless by definition.”