This investigation is concerned with testing a causal model linking changes in a political system's socio-economic environment with alterations in political characteristics. The specific forces of interest are those relating to urbanization and industrialization, the development of that way of life called urbanism, and the effects of these environmental changes on voter participation and, ultimately, inter-party competition. The test model hypothesizes that the processes of urbanization and industrialization together create urbanism, which then affects party competition both indirectly by means of stimulating participation, and directly as well. To illuminate these processes, this study focuses on the American South of the last 30 years because it is in this region that the kinds of changes implicit in the test model have been observed, and thus the region offers the best arena for examining that model.