A Longitudinal Comparison of the Effects of Election Outcomes on System Legitimacy in the United Kingdom and United States

Abstract

Using three-wave panel data from the United Kingdom (N = 604) and the United States (N = 512), we examined changes in system-legitimization across the 2024 electoral cycle and whether trajectories differed for electoral winners and losers. In both countries, system-legitimization increased after the election, suggesting that elections function as legitimacy-relevant events once outcomes become known. Winner–loser dynamics qualified these patterns. In both countries, electoral winners showed clear post-election increases in system legitimization. Among losers, responses depended on how political alignment was operationalized. In the United Kingdom, right-leaning losers increased in system legitimization when defined by ideology, but Conservative Party supporters showed no substantive post-election change. In the United States, left-leaning losers showed little ideological change overall, whereas Democratic Party supporters exhibited a short-term decline that was not sustained 1 month later. These findings suggest that elections shape system attitudes, but loser responses are contingent on political context and how electoral alignment is defined.