Fiscal integration as a Pareto improvement
Fiscal integration in a currency union is generally understood as a transfer from fiscally strong to fiscally weak countries. I show that this changes when common debt is paired with a non-defaultable common tax, even if national debt remains defaultable. The risky country gains from intertemporal trade: it receives a grant financed by a perpetual obligation it discounts more heavily than lenders do. The cost to the safe member is second-order and the tax removes it by insuring imperfectly correlated cycles rather than transferring resources in expectation.