So, what difference do leaders make? : Candidates’ images and the 'conditionality' of leader effects on voting

Do leaders make a difference? Are national political candidates and their public images influential in shaping voter choice and in determining election outcomes? Scholarly literature on “leader effects” tends to be discordant when assessing the impact of leader images on voting. This suggests that we should reframe the question in “conditional” terms, i.e. under what conditions do leaders make a difference? Indeed, we need to consider not only “how much”, but also “who” can make a difference along with “where”, “when”, “to whom”, and “how”. Having examined the findings of existing international research, this review article proposes an “epistemological tool kit” with which to examine the forms and limits of knowledge on the influence of leaders’ images on voting. In so doing, it considers the following “conditions of possibility” for leader effects: (1) structural constraints: the institutional, political, territorial and media contexts in which an election takes place; (2) political opportunities: the opinion climate, the economic situation, the presence of a systemic crisis, and the campaign environment; (3) individual moderators: the availability of leader-oriented segments of voters; (4) image variables: the fundamental features of the candidates/leaders. Finally, the article examines the possible forms (types of effects and mediating processes) and impact (micro/macro assessment) of leader effects on voting.