When the radical political theorist HP Newton faced the popular psychoanalyst EH Erikson across a table in the library of a Yale college their discourse reflected that between Lenin and Rosa Luxemburg on the Polish question half a century earlier. After the rise and fall of the Soviet Union the same questions still burn just as fiercely today. This book records and charts these dialectics and shows how Newton's vision of intercommunal identity expresses a Kantian categorical imperative which can be applied to the historical specifics of Jewish, Irish and Welsh nationalism within and beyond the European community.