Are election campaigns relevant to policymaking, as they should in a democracy? This book sheds new light on this central democratic concern based on an ambitious study of democratic mandates through the lens of agenda-setting in five West European countries since the 1980s. The authors develop and test a new model bridging studies of party competition, pledge fulfillment, and policymaking. The core argument is that electoral priorities are a major factor shaping policy agendas, but mandates should not be mistaken as partisan. Parties are like ''snakes in tunnels'': they have distinctive priorities, but they need to respond to emerging problems and their competitors'' priorities, resulting in considerable cross-partisan overlap. The ''tunnel of attention'' remains constraining in the policymaking arena, especially when opposition parties have resources to press governing parties to act on the campaign priorities. This key aspect of mandate responsiveness has been neglected so far, because in traditional models of mandate representation, party platforms are conceived as a set of distinctive priorities, whose agenda-setting impact ultimately depends on the institutional capacity of the parties in office. Rather differently, this book suggests that counter-majoritarian institutions and windows for opposition parties generate key incentives to stick to the mandate. It shows that these findings hold across five very different democracies: Denmark, France, Germany, Italy, and the UK. The results contribute to a renewal of mandate theories of representation and lead to question the idea underlying much of the comparative politics literature that majoritarian systems are more responsive than consensual ones.