This study proposes a framework for analysis in which the correlation between the principal variables, events and procedures, which in their combined interaction serve to determine a state's international role, is illustrated in causal sequence. This model then provides the theoretical framework for the analysis of the role of Nigeria in international politics. Three criteria are identified as fundamental in determining a state's external behaviour: first, the spectrum of national capability resources, which constitute the physical and non-physical characteristics of the state; secondly, the notion of ego-role perception, which is the product of the perception of state leadership of the threats and opportunities arising from the state's interaction with the international environment in which the objectives of policy must be realized; and thirdly, the notion of alter-perception, which arises from the premise that the first two criteria are essentially relative to the perception of the major world powers. Nigerian behaviour in the international system is the product of the interaction between the capability means of population size, economic leverage and military capability. These capability means are mobilized in pursuit of certain ego-role objectives (namely the aspiration to be both an honest-broker and a continental leader) and the maintenance of national unity and stability. These ego-role objectives are realized in the international system primarily by diplomatic means, supported by threats of economic retribution or military action. The pattern of this national strategy for interaction has, over time, established a positive perception of the significance of Nigeria for the members of the global system and the African sub-system. Nigeria has created a role which combines continental leadership with sub-systemic predominance.

International boundaries inherited from colonialism have given room to territorial disputes and the existing boundary conflicts in the West African Region, and are an endemic feature of Nigeria's relations with her immediate neighbours. The thesis examines the 18 border disputes that Nigeria has been involved in since independence. The thesis begins by setting the scene in terms understanding Nigeria's foreign policy principles and objectives since independence and, in particular, its policy towards border disputes across the continent of Africa such as the Congo/Katanga, Uganda/Tanzania, Ethiopia/Somalia and Morocco/Algeria (chapter 2). The thesis then moves on to consider the underlying problems that have faced Nigeria as regards its borders as a result of colonisation (chapter 3). As the history is traced of the stages in the definition of Nigeria's boundaries, it becomes apparent that many border issues were unresolved or that decisions were made that were likely to be contested in the future. In chapter 4 the thesis turns to a detailed examination of the border disputes that have arisen in the last 43 years of independence between Nigeria and her close neighbours, Benin, Chad, Equatorial Guinea, Cameroon and Niger. Chapter 5 analyses the data provided. It finds that the way the dispute was handled was closely related to the regime type. Under the liberal democratic regimes of Balewa, Shagari, Obasanjo II, disputes were largely dealt with by diplomacy and negotiation. Whereas under the autocratic regimes of military leaders such as Generals Ironsi, Gowen, Muhammed, Obasanjo, Buhari, Babangida, Abacha's and Abubaker's the disputes brought a response of a threat of force or aggressive use of force. It concludes that liberal democracy profoundly affects how border disputes are handled and is a force for peace and stability.