Approved for public release; distribution is unlimited / This thesis explains the military relationship between the United States and Pakistan in the context of their divergent national security interests. During the Cold War, U.S. concerns focused on the global contest between democracy and communism. In this competition, Pakistan was seen as an important ally. However, Pakistan viewed India as its primary threat and considered global ideological concerns as secondary in importance. At times, each country benefited from the other, but neither ever fully met the other's most important needs. The United States did not support Pakistan in its wars with India and Pakistan did not confront communism except to help oust Afghani governments non-compliant with Pakistan's interests. Pakistan's military held power for more than half of Pakistan's existence and became the U.S.' key ally in South Asia. Pakistan's pursuit of nuclear weapons distanced U.S. relations in the post-Cold War environment. The terrorist attacks of 11 September 2001 catapulted Pakistan's importance as an ally but at the cost of supporting a military regime and the erosion of a democratic government in Pakistan. This thesis argues that Pakistan's military now shares a relationship with the United States that builds regional stability but which may also hold political consequences in the United States. / Major, United States Marine Corps