The dynamics of dominance and compromise

Political goals are often sought by groups, whether they be political parties, trade associations, interest groups, or of any other sort. The formalities of modern political systems rely on individual voting, but group identities shape both individual behavior and the workings of government. To build a metaphor from the natural sciences, fluids (groups) are composed of molecules (individuals), but the fluid has properties of its own that affect its motion (actions) and interactions with other fluids (groups). This paper develops a model based on fluid dynamics relationships to explain group interactions based on observable group characteristics. It complements many strands of literature by explaining the circumstances in which existing models are valid, and in which they are incomplete. In so doing, it does not refute any existing models, but links them together and addresses their shortcomings.