Many contend that U.S. state parties are increasingly polarized and nationalized, meaning that they have adopted divergent positions matching their national counterparts’ positions. Such trends reflect a transformation of America's historically decentralized party system. Yet, the precise timing of these related trends—as well as the mechanisms underpinning them—remain unclear. We assess these dynamics using a novel data set of 1,783 state party platforms between 1918 and 2017. Applying tools from automated and manual content analysis, we document a dramatic divergence in the topics emphasized by Democrats and Republicans starting in the mid-1990s, just as congressional speech became polarized. During this period, cross-state differences in each party's agenda decreased and regional/sectoral issues became less prominent, suggesting tight connections between polarization, nationalization, and state agendas. We also find that innovative phrases increasingly debut in state (not national) platforms. Overall, the evidence undercuts claims of top-down polarization emanating from national party leaders in Washington, DC. Polarization at the state and federal levels coincided with the development of an integrated network of activists spanning multiple levels of the polity.

Using data from the 1956–60 and 1972–76 National Election Studies (NES), we replicate the issues/party identification (PID) models set forth in Franklin (1992) and Franklin and Jackson (1983). Mild constraints on the signs of the parameters in a full-information model reduce to insignificance the apparent causal influence of issue proximities on partisanship. Furthermore, alternative specifications of the issues/PID relationship yield no evidence that citizens update their partisanship based on their ideological distance from the parties.

Poole and Rosenthal's NOMINATE scores have been a boon to the study of Congress, but they are not without limitations. We focus on two limitations that are especially important in historical applications. First, the dimensions uncovered by NOMINATE do not necessarily have a consistent ideological meaning over time. Our case study of the 1920s highlights the challenge of interpreting NOMINATE scores in periods when party lines do not map well onto the main contours of ideological debate in political life. Second, the commonly used DW-NOMINATE variant of these scores makes assumptions that are not well suited to dealing with rapid or non-monotonic ideological change. A case study of Southern Democrats in the New Deal era suggests that a more flexible dynamic item-response model provides a better fit for this important period. These applications illustrate the feasibility and value of tailoring one's model and data to one's research goals rather than relying on off-the-shelf NOMINATE scores.

Few transformations have been as important in American politics as the incorporation of African Americans into the Democratic Party over the course of the 1930s–60s and the Republican Party's growing association with more conservative positions on race-related policies. This paper traces the relationship between New Deal economic liberalism and racial liberalism in the mass public. A key finding is that by about 1940, economically-liberal northern white Democratic voters were substantially more pro-civil rights than were economically-conservative northern Republican voters. While partisanship and civil rights views were unrelated among southern whites, economic conservatives were more racially conservative than their economically liberal counterparts, even in the south. These findings suggest that there was a connection between attitudes towards the economic programs of the New Deal and racial liberalism early on, well before national party elites took distinct positions on civil rights. Along with grassroots pressure from African American voters who increasingly voted Democratic in the 1930s–40s, this change among white voters likely contributed to northern Democratic politicians' gradual embrace of civil rights liberalism and Republican politicians' interest in forging a coalition with conservative white southerners. In attempting to explain these linkages, I argue that the ideological meaning of New Deal liberalism sharpened in the late 1930s due to changes in the groups identified with Roosevelt's program and due to the controversies embroiling New Dealers in 1937–38.

The seemingly wide opening for liberal domestic policy innovation by the U.S. federal government in the early-to-mid-1930s gave way to a much more limited agenda in the late 1930s and 1940s. The latter years saw the consolidation and gradual extension of several key programs (e.g., Social Security and Keynesian macroeconomic management), but also the frustration of liberal hopes for an expansive “cradle-to-grave” welfare state marked by strong national unions, national health insurance, and full employment policies. Drawing upon rarely used early public opinion polls, we explore the dynamics of public opinion regarding New Deal liberalism during this pivotal era. We argue that a broadly based reaction against labor unions created a difficult backdrop for liberal programmatic advances. We find that this anti-labor reaction was especially virulent in the South but divided even Northern Democrats, thus creating an effective wedge issue for Republicans and their Southern conservative allies. More generally, we find that the mass public favored most of the specific programs created by the New Deal, but was hardly clamoring for major expansions of the national government's role in the late 1930s and 1940s. These findings illuminate the role played by the South in constraining New Deal liberalism while also highlighting the tenuousness of the liberal majority in the North.

Studies of mass political attitudes and behavior before the 1950shave been limited by a lack of high-quality, individual-level data.Fortunately, data from public opinion polls conducted during thelate New Deal and World War II periods are available, although themany difficulties of working with these data have left them largelyuntouched for over 60 years. We compiled and produced readily usablecomputer files for over 400 public opinion polls undertaken between1936 and 1945 by the four major survey organizations active duringthat period. We also developed a series of weights to ameliorate theproblems introduced by the quota-sampling procedures employed at thetime. The corrected data files and weights were released in May2011. In this article, we briefly discuss the data and weightingprocedures and then present selected time series determined usingquestions that were repeated on 10 or more surveys. The time seriesprovide considerable leverage for understanding the dynamics ofpublic opinion in one of the most volatile—and pivotal—eras inAmerican history.

The reversal in the parties’ positions on civil rights is widely viewed as one of the most important political transformations in the last century. Drawing upon new indicators of members’ support for civil rights—which more effectively gauge preferences than do the roll-call-based measures analyzed in previous studies—we show that northern Democrats displaced northern Republicans as the leading advocates of civil rights in the House beginning in the mid-1940s, and that the gap gradually increased thereafter. Rather than a relatively sudden change driven by national party elites, we argue that the civil rights realignment was a response to the two parties’ coalitional partners.

Few transformations have been more significant in American politics in recent decades than the Democratic Party's embrace of racial liberalism and Republicans' adoption of a more conservative stance towards civil rights-related policies. We hypothesize that pressure to embrace a liberal position on civil rights was much stronger among northern Democrats and their coalitional partners than among northern Republicans and their affiliated groups by the mid-1940s, as the Democrats became firmly identified as the party of economic liberalism and labor unions. To test this hypothesis and develop a more fine-grained understanding of the dynamics of party positioning on civil rights, we collect and analyze a new data source: state political party platforms published between 1920 and 1968. These unique data suggest that Democrats had generally become the more liberal party on civil rights by the mid-to-late 1940s across a wide range of states. Our findings – which contradict Carmines and Stimson's prevailing issue evolution model of partisan change – suggest that there were strong coalitional and ideological pressures that led the Democrats to embrace racial liberalism. This finding not only leads to a revised perspective on the civil rights revolution, but also to new insights into the dynamics of partisan realignment more generally.