The internationalisation of TG is now a fact. What are external actors, when providing assistance to TG, legally prevented from doing? They must in any event respect, and refrain from obstructing, the obligations incumbent on TA. They must avoid any misalignment with the minimum common denominator of emerging customary rules in relation to TG. This translates into concrete prohibitions for external actors who are prevented from imposing TG; altering the limitations ratione temporis and ratione materiae to the interim rule; undermining inclusivity; and impeding domestic TJ efforts. More generally, they have an obligation of moderation and must respect the fiduciary nature of TG serving a specific goal: the progressive and inclusive realisation of self-determination. The level of intensity of these norms and prohibitions (and potential engagement of their international responsibility) depends on the legal force of the core obligations from which they are derived or on the extent to which said principle has effectively gained precision through them.

TG is often subject to high-voltage politics. Yet, it is not entirely immune from normativity. This book showed that the impact of international law is increasingly being felt in the field of TG, and furthermore suggested that TG norms and practices are, conversely, enriching international law, even if only modestly by adding non-negligible detail to some of its pre-existing fundamental principles. The current emergence of customary rules in relation to TG, testified by a perusal of practice, does not itself happen in a normative vacuum.

After 1989, the function of TG changed. It became a process whereby TA introduce a constitutional transformation on the basis of interim laws. In spite of its domestic nature, it also became an international project, and one with formidable ambitions: ending war, conflict or crisis by reconfiguring the state order. This model attracted international attention, notably from the UN Security Council, and became a playing field of choice in international politics. Also without recourse to armed force, international actors could impact a state apparatus – through state renaissance. This book zooms in on the non-forcible aspects of conflict-related TG while focusing on the transition (notably by replacement or transplacement) itself. The journey becomes the destination. This study will show that, less and less so and except if the ongoing development of the law applicable to TG itself embarks upon a sea change, neither TA nor external actors can act legibus soluti when realising or contributing to state renaissance.

TA, whether consensual or oppositional, have a civilian nature or portfolio and are to be contrasted with armed opposition groups and NLM. Their finality is not armed struggle but the exercise of political power during the interregnum in view of a state renaissance in a specific historic context: the rise of the peace-through-transition paradigm since the end of the Cold War. The role of contemporary TG has been aggrandized in this sense. TG is by definition pursued on a provisional basis, and can be divided into four stages, with the two middle stages (foundation and interregnum) being most relevant. During the interregnum, the redefinition of the state order is an exercise of public power, and eminently so. TA, even without being allotted governmental status (as of yet), may enjoy legal personality to the extent that they effectively exercise such power, are seen as addressees of international obligations, or (subsequently) come to represent the state.

Indirect regime change is, in principle, forbidden under international law because it affects the heart of a state’s domaine réservé. The inducement of oppositional TG aims at indirectly reconfiguring the constitutional order of the target state through TG. Applied as a coercive unilateral measure, it is hard to sustain that this practice complies with the principle of non-intervention. This conclusion suffers a theoretical and rather improbable exception: the scenario of constitutional texts explicitly and directly validating ius cogens violations. Another exception, which could become less theoretical, is when the UNSC induces an oppositional transition under Chapter VII of the UN Charter, or authorises states to do so as a way to cope with a threat to or breach of international peace and security. In such cases, the UNSC could only empower an oppositional TA after a conscientious assessment of the TA’s compliance with ius in interregno.

The recourse to TG is flourishing, especially as state creation has passed its zenith, and ITA is considered too costly while also being normatively contested. Through TG, international involvement can furthermore be cost-efficient and discrete while leaving its marks on virtually all state renaissance components. In addition, some might try to argue that TG is preferable on pseudo-legal grounds. In any event, state transformations are subject to internal and external influences in many fields, including a field going to the core of a state’s business: regime transformation and reconstitutionalisation. TG is placed centre stage in international diplomacy, and already plays an important role for the international security system. In public discourse, external involvement is often associated with the peace-through-transition paradigm and the assistance model. Yet, such discourse barely conceals that goals other than international peace and security namely constitutional geopolitics – can be pursued through assistance to TG.

As to the sources of ius in interregno, both stable and evolving norms applicable to TG should be considered. Individual customary rules are germinating in relation to TG but not in isolation from the existing principles of self-determination and non-intervention. As to the evolving part of ius in interregno, TI may testify to the emergence of custom. Both domestic laws, unilateral declarations, intrastate agreements or international conventions can be taken into account. Socialisation explains why these and other instruments incorporate TG-relevant patterns. The effects of dominant discourse and mimesis entice a common (legal) culture accounting for both the (socialised) origin of, and (legal) compliance with, specific behavioural patterns. This fertile breeding ground also explains why such patterns are formalised through the adoption of TI, which may or may not be valid on the domestic plane: compliance with international law is expected regardless of how the transition was triggered.