Scholars have long debated whether parties are responsive to the general electorate or partisan constituents. Yet, beyond the role of party type, we still know surprisingly little about when parties may favor one responsiveness model over the other. I shed light on the decision rules that govern whether parties attempt to consolidate their support base by adapting to the demands of partisan constituents and when they instead try to expand their electoral coalition through strategies that reach out to citizens who previously did not cast their vote for them. I combine election study data on voter preferences with expert survey information on party positions to study responsiveness in over 200 parties from 28 European countries between 1999 and 2019 across six key policy issues. The findings demonstrate that election-, party-, and issue-level factors all play a crucial role in parties’ decision-making process concerning which responsiveness model to follow. Preliminary analyses suggest that high electoral volatility, vote gains, and high issue salience amongst supporters steer parties towards the partisan constituent model. The paper has important implications for our understanding of party responsiveness and voter representation in contemporary European politics.