As the Roman Empire spread two millenniums ago, maps had to be redrawn to reflect new realities. In similar fashion, the expansion of the British Empire kept cartographers at their drawing boards, reshaping territories from Southern Africa to India to Hong Kong.

Now, as the United States wages its war on terrorism in Afghanistan - and deploys troops for the first time in the energy-rich regions of Central Asia and the Caucasus - the borders of a new American empire appear to be forming.