What would constitute an economically rational choice for Greece, given the economic and political situation? I see four options, each of which is fraught with uncertainty.

The first would be the status quo: more austerity and economic reforms as outlined by the International Monetary Fund and the EU. One risk is that this would keep Greece in an eternal depression and a debt trap, where economic output fell faster than growth. Another is that, while on paper it might just work economically, it would almost certainly fail politically.

Indeed, that may already be happening. Syriza, the hard-left anti-austerity party, heads the latest opinion polls. If this result were replicated at a future election, it would also obtain the coveted prize of 50 additional parliamentary seats, a sixth of the size of the entire parliament. So this would end up with the triumph of extremist parties.