People around the globe have embraced democracy to bring about positive social change to address our environmental, economic, and militaristic challenges. Yet, there is no agreement on a definition of democracy that can guide social change efforts. The Polarities of Democracy model is a unifying theory of democracy to guide healthy, sustainable, and just social change efforts. The Polarities of Democracy model consists of ten elements, organized as five polarity pairs: freedom & authority, justice & due process, diversity & equality, human-rights & communal-obligations, and participation & representation. In this model each element has positive aspects and negative aspects and the objective is to successfully manage the polarities so as to maximize the positive aspects and minimize the negative aspects.