Although parties focus disproportionately on favourable issues in their election
campaigns, it is also the case that parties spend much of the `short campaign' ad-
dressing the same issues { and especially salient issues. This is surprising from the
perspective of the theoretical literature, which has focused on parties' incentives to campaign on `owned issues' in order to increase the importance voters attach to these issues. We explain this behaviour by proposing that parties face an additional incentive to emphasise issues that are salient to voters: the need to clarify their positions on these issues for sympathetic voters. Leveraging the surprise election victory of the British Conservative Party in 2015 -- which prompted a hitherto unexpected referendum on EU membership -- we show that, consistent with this
hypothesis, voter uncertainty is especially costly for parties on salient issues. We formalise this argument using a model of party strategy with endogenous issue salience.
