This book highlights the effects of institutionalized territorially constituted coalitions in EU Council negotiations by focusing on the Nordic-Baltic cooperation throughout three case studies. The main argument is that institutionalized coalitions bestow their rationally-acting members with a bargaining advantage, even if they cannot generate enough voting weight to reach voting thresholds. Cooperation within institutionalized coalitions enhances the bargaining power of its participants through three mechanisms: an exchange of information, which counterbalances the asymmetries in information distribution in the pre-negotiation stage; the pooling of expertise that allows the Member States to share resources and provides common argumentation for their positions; and the 'rhetorical action' that gives more strength to normative justifications.