One of Lenin’s most important contributions to Marxist theory are his writings on the right of nations to self-determination. Drawing on Marx’s dictum that a nation which oppresses another cannot be free, Lenin argued that working-class unity could not be built without workers in the oppressor nation recognizing, and fighting for, the national rights of oppressed nations. Lenin’s views have implications for not only understanding national oppression and its relationship to the fight for socialism, but for approaching other forms of oppression under capitalism.