The coup in Bolivia kind proved that even social democracy is off the table if it interferes with imperialist interests.
This is a problem that all anti-capitalist ideologies have to face.
The capitalist hegemony has an interest in preventing nations from shifting away from the status quo, so socialist, anarchist, whatever revolution that is fought, however it is fought. It will have to carry out some practices that would be decried as authoritarian to protect themselves from outside interference.