Aside from Iraq, the other two "axis of evil" nations have been on the minds of U.S. policymakers of late. Last Thursday, Iran missed its deadline to comply with a UN resolution requiring the cessation of its nuclear program. The same day, the Defense Department successfully tested its controversial missile defense system (WashPost), which in part, is designed to protect U.S. targets from the specter of North Korea's ballistic missiles. But aside from giving U.S. officials fits, Iran and North Korea have another thing in common, they both have had extensive dealings with Dr. A.Q. Khan. The "Father of the Islamic Bomb," Khan is seen as a national hero in Pakistan for providing his country with a nuclear deterrent against its archrival, India. He is also one of the world's most notorious criminals, the former head of a network that distributed nuclear technology on the black market (Globalsecurity.org) to Iran and North Korea as well as Libya. The network inspired nightmares for nonproliferation and security officials, and former CIA Director George Tenet even described Khan as "at least as dangerous as Osama bin Laden" (BBC).
By 2003, Western intelligence officials were onto Khan, and that October they managed to intercept a shipment of centrifuge parts destined for Libya. The seizure marked the beginning of the end for the Khan network: The following year, Khan was forced to make a televised confession, after which he received a presidential pardon and was confined to house arrest in his multi-million dollar villa (Atlantic) (subscription only). The Carnegie Endowment for International Peace tracks Khan's trajectory in this timeline (PDF), and the Wall Street Journal reviews a new book about Khan's dealings.
U.S. officials claim the Khan network has been dismantled and the Pakistani government says the case is closed, but according to testimony before the House Subcommittee on International Terrorism and Nonproliferation, that is not the case. ISIS President David Albright testified that International Atomic Energy Agency officials have not yet been able to question Khan directly and "key questions remain unanswered" (PDF). Leonard Weiss, an independent nonproliferation expert, told Congress, "At least some parts of the network are definitely still functioning" (PDF). Meanwhile, Pakistan has been accused of interfering with investigators' inquiries. As journalist Steve Coll says in a Q&A on the New Yorker's website, "It's presumed that one reason is that Khan knows quite a lot about how Pakistani generals and other leaders have endorsed or profited from his global trade."
The story of A.Q. Khan underscores the importance of nonproliferation efforts in an era when technology and expanding trade increasingly favor smugglers. Such a challenge requires a creative solution, and the Proliferation Security Initiative, a project of the Bush administration, may hold some of the answers. An interactive guide from MSNBC describes how renegade nations may go about concealing their own nuclear programs.
Of course, one of the greatest fears is the prospect of terrorists detonating a nuclear weapon. A CFR Special Report, Preventing Catastrophic Nuclear Terrorism, has a number of recommendations for keeping weapons out of terrorist hands. The porous U.S. borders are one line of defense that could use shoring up: In March the Government Accountability Office told the Senate how undercover agents successfully smuggled radioactive material across the borders with Canada and Mexico. In congressional testimony, CFR Senior Fellow Stephen E. Flynn outlines a scenario in which terrorists might successfully smuggle a warhead into the United States. The impact of a nuclear terrorist attack on U.S. soil is discussed by CFR Fellow Michael A. Levi in this podcast, and illustrated by this blast calculator from the Federation of American Scientists.