LONDON – Gung-ho about the fall of Kabul, but wary about the political morass that now confronts it, the U.S. has thrown the ball to the United Nations, an organisation not normally held in high regard in Washington but, as on past occasions, a useful refuge in times of grave crisis. Yet if history is any guide, a wave of amnesia about the value of the UN will fall over Washington as soon as the matter in hand has been dealt with. It has long been so. In 1954 there was the incident of the capture of seventeen U.S. airmen over China. Just as in the later Iranian hostage taking-taking, American opinion became extremely agitated. There was even some wild talk about the use of nuclear weapons. The UN was asked to intervene and Secretary-General Dag Hammarskjold went to Beijing to talk to Premier Chou En-lai. It took six months...