We examine the effects of individual political preferences and the distribution of such preferences on the social transmission of political information. Our data base combines a 1984 election survey of citizens in South Bend, Indiana with a subsequent survey of people with whom these citizens discuss politics. Several findings emerge from the effort. First, individuals do purposefully construct informational networks corresponding to their own political preferences, and they also selectively misperceive socially supplied political information. More important, both of these individual-level processes are shown to be conditioned by constraints imposed due to the distribution of political preferences in the social context. Thus, individual control over socially supplied political information is partial and incomplete. Finally, these information-transmitting processes interact with the social context in a manner that favors partisan majorities while undermining political minorities.