This report aims to analyse the capability of the Collective Security Treaty Organization (CSTO) for collective military intervention in quickly emerging localized conflicts on or near the member states' territories. The CSTO, formed in 2002, today consists of Armenia, Belarus, Kazakhstan, Kyrgyzstan, Russia and Tajikistan. It is gradually evolving from a military alliance to a more multifunctional organization addressing many security issues. Russia, by far the biggest member, dominates the organization's development and contributes most resources, but needs the cooperation of the smaller states to enhance its legitimacy. The CSTO is probably the main effort to build both capacity and legitimacy for possible military intervention to address security concerns in Central Asia as the international military effort in Afghanistan is being reduced. As of early April 2013, however, the CSTO remains untested in reality. The CSTO has two types of forces. First, in the past decade it has developed and regularly exercised regional force structures in Eastern Europe (Western Russia and Belarus), in the South Caucasus (Armenia) and in Central Asia (Russian forces and the forces from Kazakhstan, Kyrgyzstan and Tajikistan). Second, there are mobile forces for deployments in all CSTO-countries. The CSTO plans to be able to field some 20 000 soldiers in a Collective Operational Reaction Force (CORF, also known by its Russian acronym KSOR), mainly consisting of highly mobile elite airborne units (primarily Russian). A smaller mobile force is the planned 4 000-men strong Peace Keeping Force (PKF), which can also be used in UN operations. Both forces exist and have exercised, but in far smaller numbers. Command and control systems in these multilateral forces seem to be dominated by Russia. The building of these multinational forces has been challenged by the asymmetry of the forces from the different member states, for example in levels of modernization and training and different equipment and procedures. The CORF is likely to be able to respond quickly and be adequate for one short conflict, but the endurance of this force is questionable. If a conflict is drawn out or if several conflicts occur simultaneously follow-on forces are needed. CSTO's ability to field additional forces essentially consists of Russian ground forces, up to one infantry brigade with supporting units for up to six months without major re-prioritizations between Russia's military districts. Other CSTO countries are likely to supply smaller units. Building the CSTO's political and military structures for joint political decision making and command of joint multilateral operations is also a work in progress. Apart from the practical problems in building joint forces, there are also conceptual challenges (basic values) and political challenges (Russia's dominance, real or perceived, or the low degree of mutual trust among many of the other members). The bottom line is that the CSTO's political will and military capacity are essentially Russia's. If the international community wants to contribute to addressing the potentially huge security challenges in Central Asia after 2014 (such as conflicts about borders and/or resources, ethnic tensions, succession struggles and Islamic militancy) there are few alternatives to interacting selectively with the CSTO, despite misgivings about its basic values, Russia's dominance or the risk of legitimizing Russian spheres of influence.