Optimal monetary and fiscal policy in a currency union

We lay out a tractable model for the analysis of optimal monetary and fiscal policy in a currency union. The monetary authority sets a common interest rate for the union, whereas fiscal policy is implemented at the country level, through the choice of government spending. In the presence of country-specific shocks and nominal rigidities, the policy mix that is optimal from the viewpoint of the union as a whole requires that inflation be stabilized at the union level by the common central bank, whereas fiscal policy has a country-specific stabilization role, one beyond the efficient provision of public goods.