In theory, eurozone member states, being monetary sub-sovereigns, should perform the fiscal stabilization function.

But in practice, they do not, either because they are restricted by the quasi-constitutional rules of the EU’s “fiscal compact,” or because their vulnerable public-sector finances leave them constrained by debt markets. 

Hans-Helmut Kotz, a former member of the executive board of Deutsche Bundesbank, Project Syndicate 10 October 2019