Why do executive agencies form coalitions? Legislative coalitions are widely theorized and studied, but less attention has been paid to executive coalitions. Executive agencies’ dependence on the political branches calls for a distinctive theory of coalition building. This article presents such a theory, arguing that agencies form coalitions to optimize their autonomy given their subordinate position in a separation of powers system by signaling to overseers that their policies are efficient and should be maintained. Bureaucrats form coalitions actively to advance their policy goals in the face of political opposition. Using data on dozens of agencies over seventeen years, I find that agencies are most likely to form coalitions when their preferences are misaligned with the president but aligned with each other. I also find evidence that coalitions send credible signals that bureaucratic policies are efficient since Office of Information and Regulatory Affairs is less likely to request regulatory revisions of policies produced by coalitions.
