In my opinion it would be impossible at least on a time scale yielding strategic surprise for any country in the world to duplicate information contained on those tapes without nuclear testing, regardless of how much money they were willing to spend or the intelligence of their scientists. There are simply too many unknowns that cannot be resolved without extensive nuclear testing. During my testimony at Dr. Lee's detention hearing in December 1999 I stated that the information that he downloaded could, if placed in the wrong hands, change the global strategic balance. Although the information itself does not convey all of the technology necessary to build deliverable weapons, it could advance the design effort enormously. Production of a weapon that would be a realistic threat still requires special nuclear materials, special engineering and fabrication skills, and a capable scientific cadre.
Nuclear weapons are the most destructive weapons ever created by humankind.
They are the only devices that can threaten the conventional military superiority of the United States. In the wrong hands the information downloaded by Dr. Lee could enable a proliferant nation to design relatively crude but effective nuclear weapons without nuclear testing. Those weapons would certainly not be as sophisticated as the weapons contained in the U.S. arsenal but they would be credible enough to influence other nations, including our own. A nation that already had nuclear weapons could use the codes to help maintain their weapons or to improve them. The information contained on the tapes could also be used to find and exploit potential vulnerabilities in U.S. weapons.