Stable Governments and the Allocation of Policy Portfolios

Different members of coalition governments typically have responsibility for different aspects, or dimensions, of policy. Such responsibilities are allocated as portfolios to government members. Given a distribution of such portfolios, final government policy is derived as the accumulation of individual members' decisions in regard to their respective responsibilities. We develop a portfolio allocation model of government formation and policy decision in multiparty legislatures. In particular, we focus on stable portfolio allocations, where a stable allocation is one that yields a policy that no legislative coalition is willing or able to overturn. Several notions of stability are considered and related to the usual concept of the core. Among the results are that although stable allocations are not guaranteed, such allocations can exist with minority governments; and that final policy outcomes associated with stable governments need not be “centrist.“