MOST people think they know what a failed state looks like. An obvious one is Somalia, where an outbreak of famine in the south was formally acknowledged by the United Nations this week. Help has started to trickle in after the Shabab, an Islamist militia, lifted its ban on aid agencies that it once termed anti-Muslim. In most ways the afflicted region epitomises the collapse of authority: extremists control roads and markets; the government is powerless outside the capital; outsiders provide what little assistance exists.