The study is a depth analysis of the Mennonite Central Committee’s Washington lobbying office, seeking to address--from both theological and sociological perspectives--the question of legitimacy. The office, organizationally embedded in an international service and relief organizations emerged in 1968 as a response to MCC’s relief work around the globe. As Mennonites have extended their service involvements throughout the last seven decades, they have repeatedly come face-to-face with an also-expanding American state. MCC Washington was a response to that historical reality, serving as a bridge between desires for authentic service and the constraints of the state. With the lobbying office, Mennonites hoped to speak out of their international experience with people affected by American policies. However, in their formal move to the capital, Mennonites found themselves in a context with institutionalized practices and a long-established discourse distinctly different from their own. MCC also faced discomfort from its constituent denominations, who were uncertain of this new political engagement. The dissertation asks how an organization like MCC Washington seeks and finds legitimation from within its two institutional contexts: its supporting bodies and Washington s religious lobbying culture. The study will shed light on how the institution of religious lobbying has evolved, and will illuminate transformations in one set of religious denominations. In a larger sense, the dissertation is a story about the pervasiveness of certain institutions and institutional practices, and about the changing face of American Protestantism.