A Korean ghost lurks at U.S.-Iran nuclear talks

Are Iran and North Korea cooperating on their nuclear-weapons programs? If so, their efforts undermine, and may preclude, Barack Obama's diplomatic attempts to address these threats separately. The issue is especially timely now as Mr. Obama's negotiators rush to make a deal with Iran.

Tehran-Pyongyang collaboration raises questions of enormous strategic importance for global counterproliferation efforts. Although publicly available information is scarce, American policy makers should pay the closest attention to the implications of such cooperation. The direct evidence, while limited, is troubling.

Not least because of the initial intermediation of Pakistani scientist A.Q. Khan's proliferation network, the potential for Iranian-North Korean cooperation has long been attractive. But within the U.S. diplomatic, defense and intelligence communities, broad understanding of such dynamics is often hampered by powerful bureaucratic "stovepipes." In the bureaucratic tribal mindset, Pyongyang is an Asia problem and Tehran is a Middle East problem.

Yet A.Q. Khan was an equal-opportunity proliferator who by his own admission sold uranium-enrichment technology and equipment to Iran, North Korea and Libya. Subsequent exchanges among these customers, including of enriched uranium, are well-documented. Although the U.S. shut down Khan's network after seizing a shipment of centrifuge equipment bound for Libya in 2003, U.S. intelligence agencies have never received an adequate opportunity to question him about his operation's full scope. In pressing Pakistan for better bilateral relations, one of Washington's highest priorities should be getting more information out of Khan, particularly on possible Iranian-North Korean connections.

In September 2007, Israel destroyed Syria's still-unfinished al-Kibar nuclear reactor, which was essentially a clone of North Korea's Yongbyon facility and had been constructed with the deep involvement of North Korean scientists. Al-Kibar's purpose was to produce plutonium to be reprocessed from the spent fuel and used for nuclear weapons. Pyongyang isn't noted for pro bono work, so who financed the Syria reactor?

Those who years ago doubted Syrian involvement in nuclear-weapons activity—notably Vice President Joe Biden and elements of the U.S. intelligence community—stressed that Syria couldn't afford the high cost of nuclear work. This suggests that Iran paid for the al-Kibar project, using its surrogate Assad regime as cover. Certainly both North Korea and Iran had much to gain by hiding illicit nuclear activity where they thought no one was looking.

Back in North Korea, the Kim regime has been enriching uranium for more than a decade, as Washington concluded in 2002 and Pyongyang admitted shortly thereafter. The enrichment program significantly expanded in 2010, in full public view at Yongbyon, unlike earlier efforts which were concealed at a still-unknown location. Where did impoverished Pyongyang obtain the financial wherewithal for such expansion?

Again Iran is the most likely source. Well before the Syria reactor project, Iran and North Korea cooperated closely on ballistic-missile programs relying on Soviet-era Scud technology. In 1998, Pyongyang launched a Taepodong missile over Japan and into the Pacific Ocean east of Tokyo. This outraged Japan, and afterward North Korea pledged to suspend all ballistic launch-testing from the Korean Peninsula, a promise it kept until July 4, 2006.

But during this time North Korea and Iran continued their intensive joint missile efforts, allowing Pyongyang to make up for its inability to conduct test launches at home by receiving telemetry and other data from Iranian test launches. Although both countries claim their respective missile programs are simply intended to launch weather or communications satellites, only the gullible (including many in Washington) have ever believed this. The real purpose has always been to develop delivery vehicles for nuclear warheads.

Since 2006, when North Korea resumed its own launch testing and exploded its first nuclear device, well-documented exchanges of high-level scientific and political visitors—often coinciding with significant nuclear or missile tests—have suggested ongoing North Korea-Iran cooperation. There have also been media and academic reports of chemical-weapons cooperation and other military sales, indicating an even more intimate relationship.

The U.S. and its allies clearly have significant gaps in their knowledge about nuclear cooperation between Iran and North Korea. But the implications of any such cooperation are profound. Given the closed nature of both rogue states, Washington is long overdue in increasing its relevant intelligence-collection efforts and re-examining whether Russia or China are also involved.

Mr. Bolton is a senior fellow at the American Enterprise Institute and the author of "Surrender Is Not an Option: Defending America at the United Nations and Abroad" (Simon & Schuster, 2007).