Fear of internal instability and of outside threats to communist regimes has led to dictatorship, the instigation of a single party, and rigid policy concerning all matters. The freedom to dissent is expressly denied and repressed. National self-determination may be denied, despite communism's anti-imperialistic doctrines. Movement is restricted. Individual and social liberties, such as freedom of association, freedom of movement and freedom of expression, are firmly repressed when perceived as a threat to the dominant ideology and its representatives.