Lisbeth Zimmermann holds the Chair of International Institutions and Peace Processes, at Goethe University Frankfurt. Her main research interests are the challenges to international norms and international organizations, as well as the dynamics of expertise.Nicole Deitelhoff is Director of the Leibniz Peace Research Institute Frankfurt (PRIF) and holds the Chair of International Relations and Theories of Global Order at Goethe University Frankfurt. Her research focuses on conflicts around international institutions, and norms and forms of political rule and its legitimation beyond the nation state. She is currently researching conflict and social cohesion.Max Lesch is a Postdoctoral Researcher at the Leibniz Peace Research Institute Frankfurt (PRIF). His research focuses on contestation and deviance in international norm dynamics, with a focus on human rights and international peace and security law, and the epistemic authority of international fact-finding missions.Antonio Arcudi is an Associate Fellow at the Leibniz Peace Research Institute Frankfurt (PRIF) and a PhD candidate at Goethe University Frankfurt. His research focuses on international norms, with a focus on the responsibility to protect, and the International Criminal Court.Anton Peez is a Doctoral Researcher at the Leibniz Peace Research Institute Frankfurt (PRIF) and a PhD Candidate at Goethe University Frankfurt. His research interests include economic sanctions, norms in international politics, and empirical social science research methods.

This timely study tests the limits of normative contestation. This team of scholars show that it is important to distinguish challenges to the application of a norm from those that challenge the very validity of the norm itself. The former may help to bring potential adherents onboard, while the latter is more likely to spell instability. This study makes an important contribution at a time when international norms seem besieged from the left and the right.

• 1: Introduction: Contestation and the dynamics of norm robustness 2: The international torture prohibition: A contested norm endures 3: The responsibility to protect: A robust but changing norm? 4: Contesting the IWC moratorium on commercial whaling: A norm weakens at the international level 5: Losing Africa? Contestation and the decline in the ICC's regional robustness 6: Bad pirates, good privateers? The surprising robustness of privateering norms 7: The Atlantic slave trade: Stabilization through contestation 8: Norm disputes: Comparative insights for theory and practice Appendix: Coding schemes for applicatory and validity contestation

Lisbeth Zimmermann holds the Chair of International Institutions and Peace Processes, at Goethe University Frankfurt. Her main research interests are the challenges to international norms and international organizations, as well as the dynamics of expertise.Nicole Deitelhoff is Director of the Leibniz Peace Research Institute Frankfurt (PRIF) and holds the Chair of International Relations and Theories of Global Order at Goethe University Frankfurt. Her research focuses on conflicts around international institutions, and norms and forms of political rule and its legitimation beyond the nation state. She is currently researching conflict and social cohesion.Max Lesch is a Postdoctoral Researcher at the Leibniz Peace Research Institute Frankfurt (PRIF). His research focuses on contestation and deviance in international norm dynamics, with a focus on human rights and international peace and security law, and the epistemic authority of international fact-finding missions.Antonio Arcudi is an Associate Fellow at the Leibniz Peace Research Institute Frankfurt (PRIF) and a PhD candidate at Goethe University Frankfurt. His research focuses on international norms, with a focus on the responsibility to protect, and the International Criminal Court.Anton Peez is a Doctoral Researcher at the Leibniz Peace Research Institute Frankfurt (PRIF) and a PhD Candidate at Goethe University Frankfurt. His research interests include economic sanctions, norms in international politics, and empirical social science research methods.

This timely study tests the limits of normative contestation. This team of scholars show that it is important to distinguish challenges to the application of a norm from those that challenge the very validity of the norm itself. The former may help to bring potential adherents onboard, while the latter is more likely to spell instability. This study makes an important contribution at a time when international norms seem besieged from the left and the right.

• 1: Introduction: Contestation and the dynamics of norm robustness 2: The international torture prohibition: A contested norm endures 3: The responsibility to protect: A robust but changing norm? 4: Contesting the IWC moratorium on commercial whaling: A norm weakens at the international level 5: Losing Africa? Contestation and the decline in the ICC's regional robustness 6: Bad pirates, good privateers? The surprising robustness of privateering norms 7: The Atlantic slave trade: Stabilization through contestation 8: Norm disputes: Comparative insights for theory and practice Appendix: Coding schemes for applicatory and validity contestation

Lisbeth Zimmermann holds the Chair of International Institutions and Peace Processes, at Goethe University Frankfurt. Her main research interests are the challenges to international norms and international organizations, as well as the dynamics of expertise.Nicole Deitelhoff is Director of the Leibniz Peace Research Institute Frankfurt (PRIF) and holds the Chair of International Relations and Theories of Global Order at Goethe University Frankfurt. Her research focuses on conflicts around international institutions, and norms and forms of political rule and its legitimation beyond the nation state. She is currently researching conflict and social cohesion.Max Lesch is a Postdoctoral Researcher at the Leibniz Peace Research Institute Frankfurt (PRIF). His research focuses on contestation and deviance in international norm dynamics, with a focus on human rights and international peace and security law, and the epistemic authority of international fact-finding missions.Antonio Arcudi is an Associate Fellow at the Leibniz Peace Research Institute Frankfurt (PRIF) and a PhD candidate at Goethe University Frankfurt. His research focuses on international norms, with a focus on the responsibility to protect, and the International Criminal Court.Anton Peez is a Doctoral Researcher at the Leibniz Peace Research Institute Frankfurt (PRIF) and a PhD Candidate at Goethe University Frankfurt. His research interests include economic sanctions, norms in international politics, and empirical social science research methods.

This timely study tests the limits of normative contestation. This team of scholars show that it is important to distinguish challenges to the application of a norm from those that challenge the very validity of the norm itself. The former may help to bring potential adherents onboard, while the latter is more likely to spell instability. This study makes an important contribution at a time when international norms seem besieged from the left and the right.

• 1: Introduction: Contestation and the dynamics of norm robustness 2: The international torture prohibition: A contested norm endures 3: The responsibility to protect: A robust but changing norm? 4: Contesting the IWC moratorium on commercial whaling: A norm weakens at the international level 5: Losing Africa? Contestation and the decline in the ICC's regional robustness 6: Bad pirates, good privateers? The surprising robustness of privateering norms 7: The Atlantic slave trade: Stabilization through contestation 8: Norm disputes: Comparative insights for theory and practice Appendix: Coding schemes for applicatory and validity contestation