Finanz und Wirtschaft, July 15, 2015. PDF. Ökonomenstimme, July 16, 2015. HTML.

The collapse in Greece is a consequence of major institutional problems:

• Political decision makers in Berlin, Paris, Brussels, Frankfurt and Washington didn’t follow the rules. This seemed optimal ex post, but is suboptimal ex ante (see Kydland and Prescott).
• The ECB’s mandate is unclear.
• The monetary system is fragile.