Do parties depoliticize issues in response to internal divisions among their supporters? This study builds on previous research that demonstrated that parties change their issue positions in response to their supporters. In addition, I study whether niche parties are more likely than mainstream parties to respond to internal divisions, as a number of studies have emerged arguing that the linkage between parties and citizens is mediated by the type of party (mainstream versus niche). By means of a pooled time series analysis of 197 parties in 14 West European countries between 1986 and 2006, this study provides convincing empirical evidence that parties depoliticize the European integration issue in response to internal divisions among their supporters. There are, however, no differences between niche and mainstream parties in their responsiveness to internal disagreement. This study has important implications for the literature on responsiveness between parties and their supporters, as well as for our understanding of the strategic behaviour of niche vis-à-vis mainstream parties.