Drawing on the Israeli ‘Immanuel Affair’ (also called the ‘Israeli Brown Affair’), we examine the complex relationship between governmentality and population compositions. In the town of Immanuel, the State attempted to establish a homogeneous population of ultra-orthodox Jews by opening it to unrestricted settlement. Rather than homogeneity however, this strategy produced a divided community, whose Ashkenazi and Mizrahi residents barely interact, and the State responded by withdrawing from its governance. Contrary to the perception prevalent in the literature on governmentality, which refers to the governed population as a homogeneous body, this case invites inquiry into forms of governing in multi-population situations whose radical heterogeneity resists the State’s homogenization attempts. We argue that examining governmentality through management of events (or Foucault’s notion of ‘the milieu’) – like the Immanuel Affair – allows for greater appreciation of the interaction between complex governance mechanisms and heterogenic populations.