In Chapter 2, we review prior work on scale, discuss obstacles to reaching inferences about the causal role of scale, and lay out our own approach to this difficult question. After surveying extent work on community size and related subjects, we discuss the concept of a political community, which may be of several sorts and of any size. In the third section, we lay out the measurement of community scale, explaining that we transform population from a linear measure into a logarithmic measure. In the fourth section, we consider the difficulty of treating scale as a causal factor. This is a complicated issue, given that the population of political communities is a slow-moving cause, not directly manipulable, and rarely subject to as-if random perturbations. As such, it falls far from the gold standard of experimental research designs. The fifth section lays out the modeling strategies employed in quantitative analyses to follow. The sixth section discusses various outcomes of theoretical interest, and the final section introduces the data sources that we rely on to measure right- and left-side variables.