This is an analytical study of the US power which has been described as the imperial system as against a policy of imperial conquest. The imperial system regulates the affairs of the world politically, economically and in international trade. While the US power grew steadily through the nineteenth and twentieth centuries, it is now at its peak. The US does not have a countervailing force of any state to contend with and is in this unique position which carries a heavy responsibility for the management of the world affairs. Against the background of the US power, this analysis deals with US relations with Pakistan and Afghanistan and highlights the fact that both states have forged new asymmetrical alliances with the US which serve the strategic interests of the United States but also protect the security interests of Pakistan and Afghanistan. The latter face a serious challenge of violence and terror unleashed by the Al-Qaeda movement, which is now in a position to destabilize Afghanistan and Pakistan. The present alliance helps to defeat the terrorist movement and provides the basis for national development for both states.