The charges against David Cameron over his Iraq policy are well founded. But there are extenuating circumstances... It is time for a root-and-branch review of the principles of British foreign policy, so that they reflect two essential things: the world as it is and not as we would wish it to be; and the British national interest. Or, to put it another way, don't do nation-building and don't intervene in other people's civil wars - we usually make things worse, as in Iraq, and the waste of blood and treasure is unforgivable. If this means hobnobbing with dictators, so be it. Only genocide and threats to world order merit military intervention, as with IS.