Nationalism wasn't banned as such - expressions of "socialist patriotism" were indeed regular features of communist party rule, and the USSR then (as Russia today) commemorates the conflict with nazi Germany as "the Great Patriotic War" - but the authorities sought to suppress "bourgeois nationalism" promoting the nation above socialist values or seeking to break away from Moscow's influence, along with excesses of chauvinism directed against other bloc members. So what the authorities viewed as legitimate patriotism was fine, so long as it didn't challenge the political status quo or membership of the wider socialist community.

In wider geopolitical terms, the communist parties meanwhile embraced national liberation movements in countries subject to western rule or political and economic domination: here nationalism was viewed as an ally in the common struggle against western imperialism, and "revolutionary democratic" movements were welcomed into the fraternal fold while explicitly communist allies in Cuba or Vietnam explicitly identified their revolutions as a continuation of the earlier fight against colonial rule.