This dissertation argues contemporary party sorting --- the phenomenon by which liberals and conservatives sorted between parties on effectively ever major policy issue in the latter part of the 20th century --- is shaped by the 1960s racial realignment. I contend the parties more easily divided on issues like abortion and gun control in the 1980s-1990s, because the parties in the electorate had already divided on civil rights in the 1960s. Left-right attitudes on civil rights have long overlapped left-right divides on essentially every other major policy issue among ordinary voters. These trends date to the earliest public opinion polls and persist even among those who know little about politics. When the parties divided on race in the 1960s, pre-existing ties between civil rights and other policy views encouraged the parties to take positions on newly salient issues, such as abortion or gun control, which reinforced this racial divide.

This worked through two complimentary mechanisms. First, once the parties begin to divide on race, conservative voters on abortion or guns begin entering the Republican coalition. This creates an incentive for Republican candidates to stake conservative positions to win the party's nomination. Second, by taking conservative positions on race correlated policies such as abortion or guns, Republican candidates reinforced their appeal to conservative Democrats in the general election.

Chapter 3 uses historical public opinion dating to the 1930s to present an exhaustive analysis of issue linkages between race and policy views. I find that (1) voters that express more conservative racial views have long expressed more conservative attitudes on essentially every other major policy issue; (2) voters expressed this package of issue attitudes before the parties established positions on many now salient policies including abortion, gun control, environmentalism, women's rights and gay rights; (3) voters who do not know where the parties stand on issues still package these attitudes together.

Chapter 4 explores the role of interest groups, politicians and media figures in constructing the contemporary alignment of party and ideology. Using the development of abortion's partisan divide as a case study, I argue that because racial conservatives entered the Republican coalition before abortion became politically activated, issue overlap among ordinary voters incentivized Republicans to oppose abortion rights once the issue gained salience. Likewise, because pro-abortion voters generally supported civil rights, once the GOP adopted a Southern strategy, this predisposed pro-choice groups to align with the Democratic party. A core argument is that pre-existing public opinion enabled activist leaders to embed the anti-abortion movement in a web of conservative causes that had become newly prominent in the Republican party. This is despite many leaders of the pro-life movement's desire to align with other liberal causes inside the Democratic party.

Chapter 5 analyzes this trend in state and sub-state level races in Southern general election contests which feature candidates that had sorted on civil rights with election contests where candidates overlap on civil rights. I find consistent evidence that attitudes towards race and civil rights propelled conservative Democrats from the Democratic party once candidates in sub-national elections had divided by racial views. In doing so, these racially conservative voters brought conservative views on other policy issues with them, too.

Chapter 6 then explores how voters who are liberal on race, but conservative on other policy dimensions, reconcile these differences. I find that these cross-pressured voters consistently update their non-racial policy views to match their pre-existing issue attitudes, but this does not happen in reverse. Finally, chapter 7 discusses the implications of this dissertation for contemporary politics in the United States and abroad.

This dissertation considers how income inequality affects attitudes towards tax policies and income redistribution. In the first paper, I adopt traditional models of the relationship between income inequality and policy preferences to incorporate income volatility. I find that greater income volatility can lead voters to prefer less progressive taxes depending on the distribution of the income shocks. Because income volatility and inequality are positively correlated, with each potentially having an opposite effect on public opinion, my model predicts that support for increasing taxes on upper incomes may not rise in the face of growing income inequality. In the second paper, I estimate the casual effect of short term, temporary changes in household income on individuals' tax progressivity preferences through a series survey experiments. I find evidence that volatility does in fact diminish preferences for tax progressivity. Respondents preferred significantly less progressive taxes when described households that had more volatile incomes regardless of the pattern of volatility over time. For the third and final paper, I develop a new, more powerful permutation procedure for analyzing two-way factorial experiments. The method is a non-parametric alternative to traditional analysis of variance (ANOVA). In Monte Carlo simulations, the procedure was better able to disentangle main factor and interaction effects than regression-based ANOVA tests, particularly when the design was imbalanced. I developed the procedure for use in the analysis of the income volatility experiments.

Theories of party power in Congress differ on the circumstances under which majority parties have the ability to shift policy outcomes away from the preferences of pivotal voters and toward the majority's preferred position. The theory of Pivotal Politics states that it is unlikely parties have such power. The theory of Conditional Party Government states that parties can influence policy outcomes when they are ideologically unified, while the Cartel theory suggests that parties can influence outcomes all of the time by controlling the agenda.

In this dissertation, I propose and test three hypotheses addressing the extent of party power using an original dataset of the legislative history of federal appropriations bills and case studies of two time periods in Congress. Appropriations bills are an effective way to study trends in Congress because they must be passed every year. In the last three decades, Congress has shifted from its traditional method of passing the 13 bills that fund the federal government individually to packaging them together in massive "omnibus" bills. I show that the decision of party leaders to create omnibus bills is a form of agenda control that allows party leaders to meet a variety of goals ranging from protecting the majority party's reputation to adopting partisan policy. Omnibus bills help party leaders meet their goals because they are multidimensional, "must pass" bills that members are reluctant to oppose. They are particularly useful in the Senate, where they provide an effective counter to the ever present threat of a filibuster.

I make three major arguments. First, I contend that the ability of a majority party to control the agenda with omnibus spending bills is independent of its degree of ideological diversity. In the last 30 years, omnibus bills have been used both when the majority party is ideologically diverse and when it is unified. Second, I contend that the likelihood a majority party will seek to control the agenda with omnibus bills depends on the ideological distance from the majority's median voter to other pivotal voters on the floor. These distances have varied over time with the ideological diversity and margin of control of the majority party. Large ideological gaps between pivotal voters are an indication that the floor is a challenging arena for the majority party and create an incentive to control the agenda. Third, I contend that the policy consequences of omnibus bills vary with the majority party's ideological diversity. Diverse parties are likely to use omnibus bills to "keep the trains running" by passing the budget, while unified parties are likely to use omnibus bills to pursue partisan policy goals.

My findings expand our understanding of the motivations of members of Congress. Theories of Congress rooted in the reelection motive state that individual behavior, and by extension, the behavior of parties, is motivated primarily by the desire to improve prospects for reelection. Evidence from the history of appropriations bills over the last 30 years suggests that ideologically unified parties will use omnibus bills to pursue policy goals even if those goals create some additional risk of not being reelected.