Donald Trump’s first term coincided with a liberal shift in American public opinion, driven largely by left-leaning and independent voters on specific issues, even as emotional hostility between the two major parties intensified. The findings are published in American Politics Research.
Political scientists describe public mood as a thermostat: when a conservative administration is in power the public tends to move left, and when a liberal administration takes office the reaction is often a move to the right. These broad patterns sit alongside a growing partisan divergence on policy.
That divergence refers to a widening gap between Democrats and Republicans on topics such as health care, taxation and immigration. Over recent decades, the two parties have drifted further apart, a trend that has been accompanied by rising affective partisanship—the personal dislike or hostility voters feel toward the opposing party.
A 2024 study highlighted by PsyPost suggested that stronger links between political disagreement and personal dislike push people into opposing ideological camps. The new research revisits these ideas in the specific context of the Trump presidency.
The authors note that a separate PsyPost study from 2023 found party identification to be remarkably stable between 2011 and 2020, implying that mood changes are more often caused by changes in issue positions among those already aligned with a party than by people switching their party attachment.
The new study was led by Alan Yang, a senior lecturer at the School of International and Public Affairs at Columbia University, and Robert Y. Shapiro, a professor in Columbia’s Department of Political Science and School of International and Public Affairs. “We were interested in whether the election of an ‘untraditional’ Republican president in 2016 may have upended or accelerated past patterns of opinion change, partisan divergence, and ‘affective partisanship,’” the researchers told PsyPost.
Because Donald Trump’s platform did not always align with traditional conservatism, it remained an open question whether a liberal reaction would occur. The researchers set out to determine whether partisan gaps continued to widen and whether the era’s emotional animus influenced how people changed their policy views.
To explore these questions, the team analysed data from the 2016–2020 American National Election Study (ANES) and the 2016–2020 General Social Survey (GSS). Both datasets employ panel designs, surveying the same individuals multiple times to track actual changes in opinions from one election year to the next.
The researchers examined 32 policy questions from the ANES and 40 from the GSS, covering government spending, racial equality, immigration, foreign affairs and social issues such as abortion and gay rights. They tracked changes in responses across the whole sample and within political groups.
Affection toward the opposing party was measured using a feeling thermometer on a 0–100 scale, where higher numbers denote warmer feelings toward Democrats or Republicans.
The analysis found a clear liberal shift across many policy areas between 2016 and 2020. Support for maintaining or increasing welfare spending, expanding government services and raising immigration levels rose notably. The researchers described this as an “(expected) liberal rebound in aggregate opinion after the election of a Republican president,” noting Trump’s non‑mainstream conservatism complicated the usual pattern.
Yet the overall liberal shift concealed a widening, asymmetrical gap between the parties. The drift was largely driven by Democrats and Independents adopting more progressive stances on government spending and racial equality, while Republican opinions tended to hold steady or move slightly to the right on some issues, such as scientific research and alternative energy.
The emotional temperature of American politics also shifted. Affective partisanship rose overall, with the most pronounced changes among Republicans. Democratic respondents maintained a steady warmth toward their own party but cooled toward Republicans by around four degrees, while Republican respondents grew warmer toward their own party by more than ten degrees and cooled toward Democrats by about eight degrees. The resulting gap widened by roughly 19 degrees, far exceeding the increase observed among Democrats.
On an individual level, the researchers found that greater affective partisanship was associated with real changes in policy views. They reported that “an increased affective partisanship level was associated with Republican partisans moving rightward and Democratic partisans moving leftward across a number of highly salient policy preferences during the period of the first Trump presidency.”
The study notes several caveats. The four‑year window occurred during an unusually turbulent period, including the onset of the COVID‑19 pandemic, meaning it is unclear whether these dynamics will persist in future election cycles.
The authors argue that the link between emotional animosity and policy opinions is complex and likely bidirectional: people may grow closer to their own party on issues to distance themselves from the other side, or vice versa. Both processes may occur simultaneously, the researchers say.
Looking ahead, Yang and Shapiro plan to extend their analysis beyond 2020 to 2024 using available panel data, with hopes of clarifying whether the observed patterns continued in the years after Trump left office.
The study, titled “Individuals and Public Opinion Change: The Liberal Rebound, Continued Partisan Divergence and Affective Partisanship 2016–2020,” was authored by Alan Yang and Robert Y. Shapiro.
