The Southern Cone countries (Brazil, Argentina, Chile and Uruguay) currently provide just under half of the troops for MINUSTAH, the UN peace operation in Haiti. In this region of the world a legacy of military rule and weak civilian control, as well as a conservative reading of sovereignty, have long stood in the way of defence policy coordination and cooperation. The foreign policy incentives offered by participation in MINUSTAH have led to considerable advances, particularly in terms of multilateralization, in Southern Cone countries'' efforts to develop a concerted and united regional policy for participation in peace operations. The paper will focus specifically on the "2x9" mechanism which brings together Defence and Foreign Ministers of the nine main contributor states, and the role of Brazil in these efforts. The latter will be placed in the context of Brazil''s larger effort to use its growing regional foreign policy clout as a platform for a wider international role in international institutions.