Research on the sources of support for the communists in interwar Poland has emphasized the role of ethnic minorities, especially the Jews. To what degree did Poland's national minorities vote for the Communist Party? Using census data and electoral returns on interwar Poland's 2*72 districts, as well as a new technique for inferring individual level behavior from aggregate level data, Jeffrey Kopstein and Jason Wittenberg generate reliable estimates of ethnic group voting behavior for the Sejm elections of 1922 and 1928. The results show that it is incorrect to speak of a unified minority vote. Communist parties received disproportionate support from Belarusans. By 1928 Ukrainians voted overwhelming for ethnonational parties. The bulk of Jews drifted into establishment politics, disproportionately supporting the pro-government bloc. Contrary to the myth of the “Jewish communist,” Jews provided only a small fraction of the electoral support for the communist parties. The evidence shows that not only were the overwhelming number of Jews not communist supporters but the vast majority of communist voters were not Jews.