Due to its relatively scarce technical and economic resources, Pakistan has relied heavily on foreign sources for both equipment and technology for its nuclear program. Since 1962, it has received assistance from China, Canada, Germany, France, Britain, and the United States. The US built the first reactor in Pakistan as a part of the "Atoms for Peace" program (see timeline). Discussions on developing nuclear weapons began in the mid-1960s under Prime Minister Zulfikar Ali Bhutto, but did not really take off until 1972, after Pakistan's defeat in the 1971 war with India. The Pakistani nuclear program took on new urgency after India's "peaceful nuclear explosion" in 1974.

Until the recent series of tests in May 1998, Pakistan, like India, never formally declared its nuclear weapons program, despite the widespread knowledge of its existence. After India's nuclear tests on May 11 and May 13, Pakistan was faced with either not testing, which would leave it open to speculations about its capability (or lack thereof) by the Indian BJP government, or conducting nuclear tests and facing US sanctions. Moreover, a few days after India's tests, the Indian Home Minister, Mr. Lal Krishna Advani pointedly told Pakistan to recognize the new strategic realities in relation to its position on Kashmir. With Kashmir being central in the Pakistani view of its relationship with India, this implicit threat probably affected Pakistan's decision to test.

US reaction to Pakistan's program has been very uneven as well as opportunistic. US Cold War strategic plans and desire for a "partner" in the region, notably during the fight to get Soviet troops out of Afghanistan, led it to look the other way during the development of Pakistan's nuclear weapons program. Despite evidence of Pakistan's nuclear ambitions, the United States provided it with non-nuclear military equipment and significant financial support. After Soviet troops were driven out of Afghanistan, Pakistan was subjected to US sanctions and rebukes more often than neighboring India. The harsh US policy has been driven at least in part by a disproportionate US concern about proliferation in Islamic countries.¹ Because of Pakistan's economic weakness, the effect of US economic sanctions has been and is likely to continue to be far greater on Pakistan than on India.

Pakistan's vulnerable position vis-à-vis India has made it more open to steps for reciprocal, bilateral limitations on weapons programs. For example, it has linked its accession to the NPT to signature by India. In 1987, it proposed a bilateral ban on nuclear testing. Pakistani governments have also proposed at various times mutual acceptance of IAEA safeguards on nuclear installations, comprehensive bilateral nuclear inspections, establishment of a nuclear weapon free zone in South Asia, and formal pledges not to produce nuclear weapons. Pakistan has also used the occasion of its own status as a declared nuclear weapons state to get more attention to its longstanding call for an international (rather than bilateral) resolution of the Kashmir dispute. India has rejected most of Pakistan's bilateral proposals. However, the two countries signed a bilateral agreement in 1988 not to attack each other's nuclear facilities.