There's no way Greece can leave the Euro quietly.
The people of Greece have suffered too much for too long at the altar of monetary union for them to be forced out without associated anger.
The EU will lose face if Greece goes: it's not possible to predict what steps it might take to recover it.
And we know financial markets are overly volatile and, despite their supposed clairvoyance, almost always caught by surprise by actual events.
Something will give if Greece is forced out of the Euro when the reality is that once the scale of the issue was recognised it was always clear that Greece could not repay its debts.
I do not know what will give: I worry for the people of Greece.
But I also worry that projects like the Euro show the capacity we now have to create structures so large that they are beyond the scale of human management, given how frail that is.
Our inability to handle the compromises needed to make progress when mistakes are discovered without recrimination and punishment being on the agenda is the biggest issue arising from the Greek crisis, in my opinion.
And I have not got an answer for that.