Traditionally, a 'plural' society has been defined as one that is ethnically diverse and whose ethnic divisions are politically relevant. Arguably, the US falls within the general purview of this definition and its implications, especially with regard to African Americans, Asian Americans, Hispanic Americans and non-Hispanic, European Americans. The principal objectives of this study are: with reference to the literature on comparative and international politics, to modify extant theoretical ideas on ethnically based political behaviours so that their scope includes a broader spectrum of phenomena; and to assess the relevance of extant theory and these modifications to the American case. As far as the second objective is concerned, the principal argument is that the American case is not unique, or even singular, in terms of the relevance of this literature, but rather constitutes a variation on the main conceptual themes of actual and potential political behaviours in ethnically diverse societies.