The socialist values, they believed, will serve as the glue binding together the most disparate of ethnic elements. In the event, it took a lot more than common convictions. It took suppression on an unprecedented scale and it took concentration camps and the morbid application of the arts and sciences of death. And even then both the Nazi Reich and the Stalinist USSR fell to ethnic pieces. Homogeneity is empirically linked to stability and, therefore, to peace, economic prosperity and oftentimes to democracy.
Heterogeneity breeds friction, hatred, violence, instability, poverty and authoritarianism.
The land thus allocated should correspond, as closely as possible, with the birthplace of the nation, the scenery of its past and the cradle of its culture. The nationalist school depended on denial and repression of the existence of heterogeneity and of national minorities. Czechoslovakia expelled the Sudeten Germans after the Second World War and the Nazis rendered big parts of Europe Judenrein. Bulgarians forced Turks to flee. Franco's Spain repressed demands for regional autonomy.