Attitudes towards the political system have often been assumed to be stable attributes that are not easily influenced by short-term forces. We examine the extent to which attention to media coverage, campaign activity and electoral outcomes can mobilize support for the political system in the context of an election campaign. Using pre-election and post-election survey panels from the United States, Britain and New Zealand, we find only small shifts in aggregate measures of system support. However, we find that there are significant shifts in system support at the individual level that can be explained by status as election winners, attention to the media, particularly serious news coverage and economic perceptions. The results have implications for the debate over measures of system support such as trust, cynicism and efficacy.