COLLECTIVE SECURITY IN POST-COLD WAR EUROPE?The main purpose of the thesis is to assess whether some kind of collective security arangement is relevant to the post- cold war security order in Europe.The vast body of recent literature making a case either for or against "collective security" (CS) in post-cold war Europe suggests that the concept of CS lends itself to different interpretations. By taking a state-centric and military oriented approach to security, chapter 2 presents the classical, universal notion of CS as a conceptual basis for analysis.As the unit of analysis is less than universial, chapter 3 introduces a typology of modified CS systembs. These "systems" are, nevertheless, consistent with the state-centric, "all for one and one for all" approach characterizing the ideal version. The modified versions are dubbed regional CS, concert-based CS, and hybrid CS. Regional CS is essentially a territorially delimited version of the universal model. It is argued that such a system has the potential of being exploited by regional hemons. Concert-based CS shares many of the features of the 19th century Concert of Europe and is a system that is more consistent with power realities. A hybrid CS system has a dual character as it is a regional CS system as well as a collective self-defence organization.Chapter 4 discusses the main mechanisms of CS, and explores factors that influence their effectiveness when applied within a modifies CS setting. It is argued that the main mechamisms of CS are the deterrent effect of overwhelming military and non-military sanctions, as well as the compulsive effect of collective resistance to aggression.The lenghty discussion in chapter 5 reflects the notion that Europe is undergoing a process of dramatic change whose outcome is impossible to predict. Thus, this thesis has taken an approach towards the "issue of Europe" that opens for several outcomes, and evaluated the relevance of Collective Security to various pøausible post-cold war scenarios. Hence, chapter 5 pulls the strings together and discusses the relevance and feasibility of the CS systems and mechanisms within 5 different interpretations of the "European security complex": 1) Europe as the European Community (basically Western Europe); 2) Europe from Poland to Portugal (non-superpower Europe); 3) Atlanticist Europe (NATO Europe); 4) Europe from the Atlantic to the Urals (Gaullist Europe or Gorbachev's Common European House), and; 5) Europe from Vancouver to Vladivostock (CSCE Europe).The different interpretations are accompanied by judgements about plausible scenarios. Needless to say, the "pictures" of post-cold war Europe are painted with a very wide brush. However, relying on Neoliberal Institutionalist scenarios and propositions concering states' propensity to cooperate, it is argued that Collective Security is relevant with respect to three interpretations of the European security complex (2, 4 and 5). However, (Neo)Realist propositions pertaining to the effects of the uneven distribution of capabilities across states, suggest that CS may not be feasible unless the system respects power realities (as in the concert-based system), or allows for collective balancing against threats stemming from non-members (as in Hybrid CS).Chapter 6 provides concluding remarks. It is asserted that it seems to be common to think that the solution to Europe's quest for å post-cold war security order is a matter of finding the right balance between institutions like the EC, NATO, CSCE, WEU, NACC and so forth. However, as Robert Keohane has argued: "Institutions do not mandate what governments pursue their own interests through cooperation". Thus, the fact that former adversaries now convene in institutions like the North Atlantic Cooperation Council (NACC) may have a far greater value than realist scepticicm would suggest.