The killing of Benazir Bhutto should remind us of just how insecure our food supplies are. Our farming systems in the West are dependent on sufficient supplies of oil and gas to power our farm machinery and to make the nitrogen fertiliser and pesticides that give us such high yields. Transport and processing of food is just as dependent on these finite fuels.
Unfortunately, most of the remaining oil is in the middle east and any cut-off of supplies from that region would be a disaster for the west and especially for its food supply system. The US has been trying for years to bring stability to the middle east to ensure that the oil keeps flowing, but the killing of Bhutto makes an insecure future much more likely.
That scenario is that after months or years of turmoil in Pakistan, an anti-west Islamist group, backed by Al-Queda takes control. They would then have nuclear weapons and even the US would not dare to intervene. With this power the Islamists would be in a position to bring about their ambition to establish a Caliphate throughout the middle east and deny the hated Infidels of oil. The resulting chaos would cause a collapse of western economies and of the food supply system.