What makes a constitution difficult to amend? Many assume it's the stringency of the amendment rules, as seen with the U.S. Constitution. However, Mexico, with similar rules, has one of the most amended constitutions globally. So, if it's not the stringency of the rules, what is it? The Politics of Constitutional Rigidity: Unveiling Pathways to Change in Mexico focuses on Mexico as a case study to explore the non-institutional factors that influence the relative ease of amendment to its constitution. This book proposes a new analytical framework for understanding constitutional change, suggesting that both formal and informal changes occur within an 'economy of change.' This framework highlights how the interplay of political parties, party systems, constitutional culture, and key political actors' decisions influence political entrenchment. Timely and original, The Politics of Constitutional Rigidity offers a systematic study of constitutional change and challenges dominant approaches to constitutional rigidity.