Understanding changes in the structure of public opinion is necessary to evaluate both contemporary claims about political divisions in Brexit Britain, as well as to uncover any long-term mapping of public opinion on the depolarization and subsequent polarization of elites from the birth of New Labour to the aftermath of the Great Recession. I assess trends from British Social Attitudes surveys, utilizing recent conceptual and methodological distinctions between different features of public opinion change. I find that the public, on average, moved to the left during the early 1990s, to the right during New Labour, and back to the left from 2010. Such oscillations are even more pronounced for positions along a welfare dimension. In contrast, average positions along a libertarian-authoritarian dimension were constant until around 2010, when the public became more liberal. Polarization of left-right opinion has increased in recent years but does not match that estimated between the mid-1980s and early 1990s, while low and stable levels of polarization are estimated along libertarian-authoritarian and welfare dimensions. Overall trends are dis-aggregated by social class, educational attainment, party identification, strength of partisanship, interest in politics, and position on Europe. Further, the relationships between positions along these three ideological dimensions vary systematically across time and between groups.

Are those things on which Americans most disagree the same things that divide liberals and conservatives or Democrats and Republicans? How has this changed over time? To answer these questions, I use 350 subjective items from five decades of the General Social Survey. Estimating disagreement with ordinal dispersion and using a novel measure of sorting by party and ideological identification, I find an increasing positive association between the two phenomena. In the 1970s, the likelihood that opinion on contentious items divided partisans was low. Since then, this probability has increased. Disagreement has been more consistently associated with higher levels of ideological sorting, though this relationship has also strengthened since the 1980s. I then ask which items and substantive domains have propelled the politicization of disagreement. I decompose the estimated coefficients between disagreement and sorting by item to quantify their contribution in each decade. I find that opinions from two domains play a large role throughout the period: public spending, and sexuality and abortion. Nevertheless, there is a great deal of heterogeneity within domains and over time. Though disagreement between Americans has increasingly sorted, a relatively small number of items drive this relationship in any one decade. Even among voters, a good proportion of disagreement remains unrelated to ideological or partisan divisions.

American political elites are today more neatly divided on a wider range of issues than at any other point in the postwar era. How have these trends affected the political socialization of American youth? We argue that two distinctive aspects of US polarization, namely ideological alignment and the emergence of non-economic issues, have formed the foundation of a generational shift in favor of the Democratic party. We find that Millennials and Gen Z display levels of ideological alignment across economic, civil rights, and moral domains that are equal to or greater than previous generations. Their liberal positions on moral and civil rights issues are not only strongly predictive of vote choice, but also tend to offset any conservative positions on economic issues – in contrast to the way previous generations resolved such ideological tensions. As such, the push for a non-economic political agenda – a popular strategy in the last few decades, especially among Republicans – might well benefit the Democrats electorally as older generations are replaced.