Are parties responsive to short-term changes in election polls? While party responsiveness to election results has received much attention, we know little about the dynamics of issue attention between elections. We argue that parties dynamically respond to the declining electoral support in the polls and adapt the issue focus of successful parties. We use supervised machine learning methods to build a dynamic measure of parties' issue attention, based on a new comprehensive dataset of more than 250,000 press releases from 68 parties across 9 countries from 2010 until 2019. The results reveal that parties indeed follow the issue lead of successful competitors. Parties' issue adaptation further increases over the electoral cycle. Our findings have important implications for our understanding of party responsiveness and the dynamics of electoral competition.