Borrowing Constitutional Designs questions the hasty adoption of semi-presidentialism by new democracies. Drawing on rich case studies of two of the most important countries for European politics in the twentieth century--Weimar Germany and the French Fifth Republic--Cindy Skach offers the first theoretically focused, and historically grounded, analysis of semi-presidentialism and democracy. She demonstrates that constitutional choice matters, because under certain conditions, semi-presidentialism structures incentives that make democratic consolidation difficult or that actually contribute to democratic collapse. She offers a new theory of constitutional design, integrating insights from law and the social sciences. In doing so, Skach challenges both democratic theory and democratic practice. This book will be welcomed not only by scholars and practitioners of constitutional law but also by those in fields such as comparative politics, European politics and history, and international and public affairs.