Pakistan has long argued that it had tight grip on the country's nuclear-weapons program. Despite mounting suspicions, Islamabad assured the world that neither it nor its scientists were involved in the proliferation of such weapons to other countries. In recent weeks, Pakistan has changed its tune. Under intense international scrutiny, Pakistan has admitted that its top nuclear scientist helped other nations build atomic bombs. That scientist has confessed, but it is still unclear whether he was, as the government maintains, acting on his own or with official sanction. Either way, it has become abundantly clear that the market for weapons of mass destruction is far less regulated than thought. The WMD arms bazaar is open for business.

Dr. Abdul Qadeer Khan is a hero in Pakistan, where he is considered the father of the country's nuclear bomb. Dr. Khan established and ran the laboratories that enriched uranium and procured the equipment that allowed Pakistan to build an atomic device. He won won global attention after stealing blueprints for uranium enrichment from a European firm for which he worked in the 1970s. Since returning home, Dr. Khan has been an outspoken advocate of "the Islamic bomb." He became a target of the International Atomic Energy Agency when his centrifuge designs -- essential to creating weapons-grade enriched uranium -- turned up in Iran. In recent weeks, pressure has mounted on Pakistan to go beyond the ritual denials of Dr. Khan's involvement in efforts to help rogue states develop nuclear weapons and seriously investigate the charges.

Last week, Islamabad conceded it was wrong and reported that Dr. Khan had confessed to helping North Korea, Iran and Iraq. Pakistan insists that the scientist's activities were for personal gain, that they were unauthorized and government officials were unaware of them. The government's claim of ignorance is bolstered by the fact that Dr. Khan ran his laboratories like a fiefdom. He was left alone to accomplish the critical task of catching up with archrival India and building an atomic bomb. In a confession to the nation last week, Dr. Khan said he supplied designs, hardware and materials to make enriched uranium to Iran, Libya and North Korea. His motives varied: financial gain, supporting other Islamic nations, deflecting attention from Pakistan. But no matter what the rationale, he insisted that he acted alone without the knowledge or approval of the government or military authorities.