washingtonpost.com: In 1982, a Pakistani military C-130 left the western Chinese city of ürümqi with a highly unusual cargo: enough weapons-grade uranium for two atomic bombs, and a blueprint of how to build one say accounts written by the father of Pakistan’s nuclear weapons program, Abdul Qadeer Khan.Khan is currently under house arrest.The uranium transfer was part of a broad-ranging, secret nuclear deal approved years earlier by Chinese premier Mao Zedong and Prime Minister Zulfikar Ali Bhutto.US officials say they have known about the transfer for decades and once privately confronted the Chinese—who denied it—but have never raised the issue in public or sought to impose direct sanctions on China for it.The transfer also started a chain of proliferation in which Khan’s nuclear smuggling network shared related Chinese design information with Libya and possibly Iran.China’s refusal to acknowledge the transfer and the unwillingness of the United States to confront the Chinese publicly demonstrate how difficult it is to counter nuclear proliferation writes the Washington Post‘s R. Jeffrey Smith and Joby Warrick. Related LinkPakistani nuclear scientist said to affirm Post article’s accuracy