This book investigates the ideological conditions inducing political actors to highlight corruption issues through valence campaigns. Using case studies and comparative analyses of party programmes, legislatives speeches and social media data, the author demonstrates that the more parties and/or candidates present a similar policy programme, the more they rely on valence campaigns. In other words, as the ideologies of parties have become increasingly similar over recent decades, the content of political competition has substantially shifted from policy to non-policy factors, such as corruption issues. These dynamics, and the ideological considerations underpinning them, also provide a novel perspective on recent phenomena in contemporary democracies, such as the growth of negative campaigning, as well as populist strategies based on anti-elite rhetoric. The book will appeal to students and scholars interested in political corruption, valence politics, populism and electoral campaigning. Luigi Curini is Associate Professor at the University of Milan, Italy, and Visiting Professor at Waseda University of Tokyo, Japan. He was selected for the 2016 International Visitor Leadership Program by the U.S. Department of State's Bureau of Educational and Cultural Affairs. His recent publications include Politics and Big Data: Nowcasting and Forecasting Elections with Social Media(with A. Ceron and SM. Iacus, 2017) and Why Policy Representation Matters: The Consequences of Ideological Congruence between Citizens and their Governments(with W. Jou and V. Memoli, 2015).