Most studies of contextual influences on political attitudes and behavior have treated geographical areas as the operative social environment. As early research on social influence processes noted, the conditions that promote consensus among inhabitants of a common environment are likely to be present in formal organizations that encourage face-to-face interaction. Churches possess many of the characteristics that should maximize behavioral contagion and are thus fertile ground for the dissemination of common political outlooks. This expectation is tested by assessing the link between theological and political conservatism in 21 Protestant congregations. The theological climate in the churches is found to contribute strongly to the members' political conservatism over and above the personal commitment of respondents to traditional Christian values and a variety of social and attitudinal variables. As churches constitute the single most widespread form of voluntary organizational affiliation in the United States, their potential political impact appears to be considerable.