The lesson of the sovereign debt crises of the 2010s, and of the outbreak of the COVID-19 pandemic is that EMU irreversibility, if not to remain a wishful statement in the founding treaties, necessitates to be completed by carefully designed ramparts for extraordinary times beside regulations...

We build an infinite horizon equilibrium model of fiscal federation, where anticipation of transfers from the central government creates incentives for local governments to overborrow. Absent commitment, the central government over-transfers, which distorts the central-local distribution of...