This thesis explores the role of regional powers in the development of regional nuclear regimes. Its central argument is that the devise of regional nuclear regimes through the leadership of regional powers is driven by both functional and strategic reasons. Functionally, regional nuclear institutions serve to provide more tailored solutions to respond to nuclear risks emerging at the local level. Strategically, the formation of sub-global institutions enables regional powers to exercise considerable influence on nuclear governance processes at both regional and global levels. And in situations where regional powers are dissatisfied with the global nuclear-institutional status quo, regional nuclear institution-building provides an incomparable opportunity to question that status quo and challenge, albeit indirectly, the preferences of the United States, their main architect. The type of leadership provided by regional powers in the establishment of regional nuclear regimes is affected dynamically by two relationships: the regional powers' relation with the United States and their relation with secondary regional players. The former relation is defined as 'global nuclear alignment' and refers to the degree of proximity of the regional power towards U.S. nuclear preferences. The latter is defined as 'regional embeddedness' and captures the degree of convergence of regional powers' nuclear preferences with those of its most proxy regional contender, as well as the level of commitment shown by the regional power vis-à-vis regional integration. The thesis argues that when both relations are low, divergence of the regional nuclear regime from global nuclear institutions is most acute. Conversely, when only one of the relations is high, the regional nuclear regime tends to converge with global nuclear institutions, either in goals or in methods. The theoretical framework is applied to investigate three cases of regional leadership as provided by Brazil, Indonesia and France in the establishment of the regional nuclear regimes in their respective regions.

The study explains the regional roles of Egypt and South Africa in the last two decades by reference to the state’s relationship with society, a variable that has long been underplayed in international relations and foreign policy literature. It suggests that the different character of this relationship in each country has shaped the opportunities and constraints affecting the foreign policy choices of both the state and societal institutions in the two countries. The study adopts a cross-disciplinary approach using debates on state capacity and its relationship with regime type in comparative politics and political economy to understand and evaluate the two countries' foreign policies in their respective regions. After analysing the impact of state-society relationships on the regional role conceptions of the state and societal actors, the study compares the performance of these actors in two case studies; the Palestinian-Israeli conflict in the case of Egypt and the Zimbabwean crisis in the case of South Africa. It concludes that although the role of each state in resolving its respective regional conflict has been less than effective, the post-apartheid democratic dispensation has provided opportunities for South African social forces to play roles that complemented, checked and balanced the role of the state, compared to their Egyptian counterparts. On the other hand, the soft authoritarian Egyptian state used its role in the Palestinian-Israeli conflict to maintain the international alliances that helped to sustain its domestic control. This constrained the state's foreign policy options. It made marketing peace as 'a strategic choice' and containing resistance movements the priorities of Egypt's intervention in the Palestinian issue. The co-optation of the Egyptian business community and the exclusion of Islamist forces by the state weakened their roles in conflict resolution, depriving the state of tools of effectiveness. In the case of South Africa, racial politics, the ANC's liberation movement psyche, and the domination of the presidency over foreign policy making have hindered the promotion of NEPAD's principles of democracy and respect for human rights in the case of Zimbabwe. However, South African civil society played a crucial role in supporting its Zimbabwean counterpart, holding the South African state accountable to its foreign policy principles and its democratic institutions, and intervening where the state's role was missing or insufficient.

In the last decade South American has been the scenario of different political crises with considerable repercussions on regional stability. In that sense, the participation of regional institutions for the solution of political crises has become increasingly important. This article seeks to understand the scope and limitations of the Union of South American Nations (Unasur) for the solution of political crises in the region. Since its origins, Unasur has sought to play an important role in efforts to maintain political stability in South America. However, while in some cases its participation has been effective; in others it has been limited or insufficient. One question remains: What determines Unasur's effectiveness in resolving political crises? This article argues that it is important to observe the interests and actions of the South American States in the face of each crisis to understand the scope of Unasur as an institution that guarantees regional stability. Adopting tools derived from structural realism, it can be observed that Unasur can be effective as long as there is agreement between the regional powers. However, if it does not exist, the action of Unasur is limited and insufficient.This article will analyze the crises of Bolivia in 2008; Ecuador in 2010; the diplomatic conflict between Colombia and Venezuela in 2009-2010; Paraguay in 2012; and Venezuela in 2013. Thus, the article not only studies the effectiveness of Unasur as a regional body, but also discusses the possibilities and limitations of political integration in South America in view of the distribution of power and competition among regional powers. / En la última década, la región sudamericana ha sido escenario de numerosas crisis políticas con considerables repercusiones en la estabilidad regional. Frente a este escenario, la participación de instituciones regionales para la solución de crisis políticas ha ido cobrando cada vez mayor relevancia. Este artículo busca comprender los alcances y limitaciones de la Unión de Naciones Sudamericanas (Unasur) para la solución de crisis políticas en la región.Unasur ha buscado jugar un papel importante en los esfuerzos por mantener la estabilidad política en Sudamérica. Sin embargo, mientras en algunos casos su participación ha sido eficaz, en otros ha sido limitada. ¿Qué determina la eficacia de Unasur para la solución de crisis políticas? El artículo postula que es importante observar los intereses y acciones de los Estados sudamericanos frente a cada crisis para entender los alcances de Unasur como institución garante de la estabilidad regional. Adoptando herramientas provenientes delrealismo estructural, se observa que Unasur puede ser eficaz en tanto existe concordancia entre las potencias regionales; sin embargo, si esta no existe, la actuación de Unasur es limitada e insuficiente. Para ello, se analizarán las crisis de Bolivia en 2008 y Ecuador en 2010, el conflicto entre Colombia y Venezuela en 2009-2010, la crisis de Paraguay en 2012 y de Venezuela en 2013. Así, el artículo no solo estudia la eficacia de Unasur como organismo de integración, sino también discute sobre las posibilidades y limitaciones de la integración política en Sudamérica, en vista de la distribución de poder y la competenciaentre las potencias regionales.

The aim of the present paper is to answer the question on how do regional powers shape the security environment within their regional subcomplex? The research interest is conditioned by the rise of powers that represent strong actors, especially in regional affairs, and which certainly influence dynamics within their region. It has been assumed that the manifestation of power at the regional level can also be transferred, to the global level leading to an elevated position of these actors in global affairs, allowing equally for the existing Western-led order to be challenged. These assumptions have been applied and tested on the example of the regional powers Russia, Turkey and Iran and their respective influence on the security dynamics in the South Caucasus as their historically common shared neighbourhood. In order to disentangle the complicated web of relationships and influential factors, the descriptive framework of the Theory of Regional Security Complexes as suggested by Barry Buzan has been outlined and applied. Based on these theoretical observations the attention has been further turned towards the empirical testing of the hypothesis which states that Russia, Turkey and Iran have exercised influence during the second Nagorno-Karabakh War 2020 that occurred between Armenia and Azerbaijan...