Mathematics education in the body politic is commonly argued as important for citizenship, the citizen and the subject but, often, the concepts remain unexamined. Based on Étienne Balibar's political philosophy, the "becoming citizen subject" is traced in antiquity, modernity and posthumanity, through strivings for democracy and its impact for mathematics education is discussed. The article argues that prevailing images of the becoming "competent", "insurgent" and "creative" citizen subject are haunted in antinomies with missing human and nonhuman others acting at the margins of history and determining the political of mathematics education.