The authors argue that the effects of economic globalization on social democratic parties in Western Europe are conditional on the position of the median voter. If the median is far enough to the right, such parties will adopt business-friendly policies because they are required to win office. Only when the median is relatively far to the left will globalization constrain social democratic parties, forcing them to adopt policies further to the right in order to retain credibility. It is on this basis the authors argue that empirical studies are misspecified unless they include an interaction between measures of globalization and the position of the median. In addition to presenting formal theoretical arguments, the article reports empirical findings from fifteen countries in the period from 1973 to 2002 that support the conclusion that the effects of globalization are indeed contingent on the median. The authors find that the effects of globalization are significant for social democratic parties only in circumstances in which the median is relatively far to the left.