Leadership and public opinion are two fundamentally important, interlinked phases of the group process in government. This chapter discusses in detail the group process in government and seek a more comprehensive statement of the phenomena in terms of discussion groups and organization groups. The leadership which one group performs for another or for a set of other groups is not dependent upon the express adhesion of the full membership of the represented groups. There are also the leadership by the boss of the party outside the machine, and the leadership by the machine in the organized government in which all groups are in tension. Public opinion bears something of the relation to government that talking bears to the full-mouth activities. Many different groups may adopt one policy, that is, become part of an opinion-activity group which reflects all of them, and which takes on a so-called individuality different from- any of them.