There are several mechanisms through which ideas are supposed to influence preferences and outcomes, but one of the most important is that ideas are embedded into institutions. This presumes that once idea-infused institutions are created, they will survive and thrive. Bureaucratic politics suggests this outcome is far from certain. This article takes a first cut at examining how idea-infused, or "missionary" institutions, survive and thrive in a world of bureaucratic politics. It suggests that missionary institutions face a tradeoff between surviving and thriving. Agencies that are insulated from other bureaucracies have a better chance of surviving, but are unlikely to influence the broad contours of policy. The reverse is also true; embedded agencies have a much lower chance of keeping their ideational mission intact, but if they do survive, their odds of thriving are greater. These hypotheses are examined by comparing the evolution of the Peace Corps and the State Department Bureau of Human Rights and Humanitarian Affairs.