Before the American voter
Keywords: Political Science.

Chapter 2: The stability of party affiliations and the existence of social cleavages between the parties are taken for granted as two fundamental features of American political behavior I examine the impact of the Great Depression on party identification using a new dataset, the California Great Registers, voter lists documenting 57 million California voter registrations for the beginning of the twentieth century, matched to contemporaneous census records. Pre-realignment, political affiliation was fluid: 10% of voters moved back and forth between the parties each cycle. Early in the century, party and social class were unrelated, but the realignment forged a Democratic majority among blue-collar workers, while most white-collar workers remained with the GOP. Social cleavages like age, race and national origin only began to map onto partisanship in the 1930's, indicating that the modern period of stable partisanship characterized by voting in groups is historically contingent, emerging out of the 1930's. Chapter 3: After 60 years of partisan stability, large numbers of voters are switching parties. From 2014-2016, 10% of voters that identified with one party moved to the other two years later. This marks the most rapid switching of party affiliation since the New Deal realignment. To contextualize this partisan volatility, I introduce a new dataset, the California Great Registers, voter lists documenting 57 million voter registrations from 1908 to 1968, matched to census records covering the same period. Before the realignment, party-switching rates were twice contemporary levels; 10% of voters switched parties every four years. Women and young people, segments of the electorate one would predict to be especially prone to switch, are as stable as the rest of the electorate. This suggests that partisan socialization was weak across the board, which I attribute to the weak relationship between group membership and party identification. The partisan instability early in the twentieth century provided promising conditions for a realignment, which came about in 1932. Because the recent increase in switching is concentrated among the young, who would be expected to have the weakest attachments, a broad-scale realignment is unlikely in the near future. Chapter 4: Probabilistic record linkage (PRL) is the process of determining which records in two databases correspond to the same underlying entity in the absence of a unique identifier. Bayesian solutions to this problem provide a powerful mechanism for propagating uncertainty due to uncertain links between records (via the posterior distribution). However, computational considerations severely limit the practical applicability of existing Bayesian approaches. We propose a new computational approach, providing both a fast algorithm for deriving point estimates of the linkage structure that properly account for one-to-one matching and a restricted MCMC algorithm that samples from an approximate posterior distribution. Our advances make it possible to perform Bayesian PRL for larger problems, and to assess the sensitivity of results to varying prior specifications. We demonstrate the methods on a subset of an OCR'd dataset, the California Great Registers, a collection of 57 million voter registrations from 1900 to 1968 that comprise the only panel data set of party registration collected before the advent of scientific surveys.