We study gains from introducing a common numerical fiscal rule in a "Union" of model economies facing sovereign default risk. We show that among economies in the Union, there is significant disagreement about the common debt limit the Union should implement: the limit preferred by some economies...

Using a quantitative sovereign default model, we characterize constrained efficient borrowing by a Ramsey government that commits to income-history-contingent borrowing paths taking as given ex-post optimal future default decisions. The Ramsey government improves upon the Markov government...