JOHN KERRY, the American secretary of state, has been in Pakistan over the past couple of days, on a tough assignment. He had to show the proper degree of sympathy over last month’s terrible massacre of schoolchildren by the Pakistani Taliban, and urge his hosts to draw the logical conclusion: they must fight all violent Islamist groups instead of picking and choosing between them. And above all, they must crack down on groups which threaten India, although they are precisely the ones which have often found discreet sponsors in high places.