"Maintain Impediments": The Carter Administration and Pakistan's Secret Uranium Enrichment Program, 1978–79

The discovery of Pakistan’s secret uranium enrichment program in 1979 and the role of A. Q. Khan’s espionage in providing Islamabad with gas centrifuge technology to enrich uranium was one of the most notorious blows to the nuclear nonproliferation regime. Since 1960, the U.S. government had been working with the Dutch, the British, and West Germans to keep gas centrifuge technology secret to limit proliferation risks, but Khan’s activities undermined the secrecy arrangements. How and when the Jimmy Carter administration learned about Khan’s espionage, that Pakistan had acquired the technology and what it was doing with it remains, however, more obscure. This paper concerns the progression of the U.S. discovery, about which new information has been declassified. Washington acquired knowledge of Pakistan’s enrichment program in stages, beginning with information on Pakistan’s “shopping expeditions” for sensitive technology, the clandestine enrichment plant underway at Kahuta, and eventually details about Khan’s role. Intelligence provided by key U.S. allies, France and the United Kingdom, was crucially important. The discovery of the Pakistani enrichment program had significant policy implications, about which more evidence has also become available. The Carter administration supported a strict nonproliferation policy when it came to power, but Pakistan presented difficult policy dilemmas. It was challenging enough to convince allies to strengthen export controls over sensitive technology. It was impossible to persuade Pakistan’s dictator, General Muhammad Zia-ul-Haq, to freeze the enrichment program. Coercion through withdrawing economic and military assistance proved unavailing, but Washington could not afford a rupture in relations with a significant ally. Hoping to “maintain impediments” to Pakistan’s nuclear progress, by mid-1979 Washington began settling on a red line: only a nuclear test would produce a tough response. The Carter administration accommodated nonproliferation policy to broader diplomatic requirements