The problem is that European authorities are bound to find it politically impossible to give in, ditch the pre-existing agreement and abandon conditionality. Economically, they also face a conflict of interest. About 80% of the Greek debt is now owed to officials, the European authorities and the IMF. The official rhetoric is that “we have done enough for Greece”.
So far, however, the Europeans have not made any present to Greece,2 only loans, initially on harsh financial conditions, then sweetened. A default would turn the loans into presents. Making it possible for Greece to comfortably default does not seem appealing at all.
National governments are elected by their citizens so they are most unlikely to act to prevent a Grexit. One more time, we have to turn to the ECB, whose essential mandate is to uphold the Eurozone.
It may be unfair, but the ECB’s duty is to announce very soon that it will do whatever it takes to keep the Eurozone whole.