It is easy to construct a scenario in which tit for tat actions by the Americans and Iranians lead to all-out war, close off the Gulf, send oil prices soaring, crash the global economy – and, if you are really going to go for it, end in nuclear conflagration. But what about the alternative outcome: that conflict between Iran and the West precipitates a counter-revolution against the mullahs and leads to and end to the 40 year Iranian theocracy?

The overthrow of the Iranian regime is the black swan event – or maybe it ought to be called a white swan...