The political system through a partisan lens: Within‐person changes in support for political parties precede political system attitudes

Although political party support and attitudes towards the political system are closely related, the temporal ordering of these associations is unclear. Indeed, prior research identifies both partisan‐led change in system attitudes and system attitude‐led change in party support. Using a ten‐year (2010–2020) national probability sample of New Zealand adults (N = 66,359), we test these associations by modelling the within‐person cross‐lagged effects between conservative and liberal party support, and political system justification. During conservative‐led governments, increases in conservative party support predicted increases in political system justification more strongly than vice versa. The 2017 shift to a liberal‐led government was met with an immediate reversal of the effects of party support on system justification, but the effect of system justification on party support took a full year to reverse. These results demonstrate people's perceptions of the fairness of the political system depend on their support for the party in power.