Deep in some industrial warren, perhaps in Pyongyang, engineers carefully machine a nuclear bomb. On the other side of Asia, maybe in Tehran, chemists fill bomblets with deadly nerve gas. Farther west, let's say in Baghdad, scientists ladle toxins into a biological warhead. U.S. officials don't have, or at least won't reveal, the intelligence that proves such sinister work is afoot. But they believe it is happening. More important, they fear it is only a matter of time before one of those nations--North Korea, Iran or Iraq--lobs a missile toward the U.S.
That is why, inside a secret factory in Tucson,...