The author sees a new doctrine that is guiding the policies of the Empire which he calls the "Gates doctrine". He credits Thomas P.M. Barnett for identifying and elucidating the doctrine in his book, The Pentagon’s New Map. War and Peace in the Twenty-First Century.
Another, more realistic, imperial vision has progressively surfaced at the Pentagon.I think it is mostly the strategies that the Empire will employ to gain "access to the necessary natural resources located in the periphery" that is a bit different than previous strategies.
...The world will be divided in two. On one side, the stable centre constituted around the United States by developed countries that are more or less democratic. On the other side, a periphery - left to its own devices - plagued by under development and violence. The role of the Pentagon will be to ensure the civilised world gets access to the necessary natural resources located in the periphery, which is inept to make use of them.