"Colonialism was one aspect of imperialism. Colonialism was based on alien political rule and was restricted to some parts of the world. Imperialism, however, underlay all colonies, extended all over the world (except where replaced by socialist revolutions), and it allowed the participation of all capitalist nations. Therefore, lack of colonies on the part of any capitalist nation was not a barrier to enjoying the fruits of exploiting the colonial and semi-colonial world, which was the backyard of metropolitan capitalism."