The introduction explains the nature of shared sovereignty and its use in fragile states to promote the rule of law. It discusses how shared sovereignty has emerged and why it is important, and offers key arguments for and against the practice. It introduces the core arguments and provides an outline of the book.

This chapter examines the normative debates around sovereignty sharing. It discusses the possible benefits of the practice and the numerous critiques of deep external intervention into fragile-state governance. It argues that three factors bear upon the perceived legitimacy of a sovereignty-sharing venture: host state consent, genuine humanitarian need, and strong observed or expected external performance in service delivery. It argues that to be perceived as legitimate by diverse audiences, sovereignty-sharing arrangements generally must rely heavily on performance.

This chapter analyzes the political factors that affect the performance of a sovereignty-sharing venture. It explains the need for a supportive political equilibrium to enable effective implementation of a joint venture that can earn performance legitimacy. Such arrangements usually rest on precarious political foundations, due to the divergent interests of the national and international partners. They are often built on compromised state consent, which leads to ambiguous agreements and to confusion and discord in the field. In particular, the chapter shows why sovereignty-sharing ventures have struggled to move beyond stopgap service provision to meet their second stated objective of advancing domestic institutional reform.

This chapter reviews the potential and pitfalls of hybrid criminal courts that blend national and international laws, procedures, and personnel. It presents a detailed case study of the Special Court for Sierra Leone to illustrate the possibility for a mixed tribunal to perform well and earn public legitimacy when the preferences of national and international partners align reasonably well with one another, and with the aspirations of the general public.

This chapter focuses on the Khmer Rouge tribunal, and the danger of building a mixed court on a fragile political foundation. It shows how distrust and feuds between the United Nations and its Cambodian partners have contributed to a problematic and unwieldy design for the tribunal. The court has been able to deliver credible justice for cases in which UN and Cambodia government interests have aligned. However, its performance and perceived legitimacy have suffered from the divergent preferences of the partners, and the tribunal has had limited impact on Cambodia's formidable rule-of-law challenges.

This chapter discusses the troubled effort to create, design, and manage a hybrid judicial process in Lebanon after the assassination of former Prime Minister Rafiq Hariri. It shows how that country's profound domestic divisions rendered the government unable to issue a clear delegation of sovereign authority. The UN Security Council therefore imposed a hybrid tribunal on Lebanon, and its legitimacy has been challenged from the start. Without strong domestic cooperation, the tribunal has been highly constrained, unable to apprehend suspects or conduct extensive outreach in the country. The Special Tribunal for Lebanon thus epitomizes the dangers of a fragile political foundation for shared sovereignty.

This chapter examines international policing in fragile states. It discusses the aims and challenges of engaging external actors in core domestic law enforcement functions, drawing from the multiple cases in which external actors and local police have shared sovereign police powers. It then examines the case of joint policing in Timor-Leste, and shows how national and international interests converged during the 2006 security crisis that gripped the country, enabling international police to step into the breach and provide important security services. However, this case also shows how interests can diverge and dissipate as crises pass, and illustrates the added challenges of performing well and earning legitimacy in domains like policing, which depend heavily on local knowledge.

This chapter explores efforts to fight corruption and impunity by sharing sovereign authority over domestic criminal investigation. It focuses on the UN International Commission against Impunity in Guatemala (CICIG), the pioneering venture in this domain, and shows how a confluence of political factors led the Guatemalan government to agree in 2007 to outsource authority over certain complex criminal investigations to UN personnel. CICIG was then able to earn strong public and international legitimacy through its performance. Nevertheless, a backlash within some circles of the Guatemalan political elite eventually led to CICIG's closure in 2019, leaving its legacy of reform in peril.

This chapter analyzes the possibilities for sharing authority outside the judicial sphere in order to curb corruption. It concentrates on the seminal experiment in this area: the Governance and Economic Management Program in Liberia, created in 2005, which granted external actors cosigning authority with certain key Liberian officials. GEMAP was able to deliver important service benefits to Liberia during the tenure of President Ellen Johnson Sirleaf, thus helping to justify deep international involvement in Liberia's domestic economic affairs. The case nevertheless shows the limits of sovereignty-sharing mechanisms in implanting sustainable reforms when domestic commitment ebbs and problematic incentive structures remain.

The conclusion ties together the major analytic findings of the book. It draws policy implications of the study, reviews recent trends, and reflects on the prognosis for shared sovereignty in fragile states.