The idea that lax accounting, a violation of security procedures, and/or plain negligence could cause a warhead to disappear from a nuclear superpower's arsenal without notice was one of the scariest scenarios in the immediate post-Cold War period. More than a decade later, it turns out these concerns weren't unfounded. Such a scenario more or less occurred at the end of August. The only surprise was where it happened--not in Russia or one of the former Soviet republics as expected, but in the United States.
On August 30, 2007, crews at Minot Air Base in North Dakota loaded a B-52 strategic bomber with air-launched cruise missiles, which were slated for decommissioning. When the aircraft landed 3 1/2 hours later at Barksdale Air Base in Louisiana, air force personnel realized that (according to estimates) six of these cruise missiles carried actual nuclear warheads. That such a mishap could occur was so hard to believe that it reportedly took almost ten hours for the chain of command to absorb the message and issue the orders that allowed the warheads to be moved to secure storage.
Most U.S. news reports of the incident emphasized that the public was never in danger. The air force continues to maintain that the weapons were in its custody at all times and that it would be impossible for them to "fall into the wrong hands." Others correctly pointed out that even if the plane crashed, the probability of a nuclear explosion was essentially zero--the warheads are designed to withstand such an accident. But that's not the point.
The point is that the nuclear warheads were allowed to leave Minot and that it was surprised airmen at Barksdale who discovered them, not an accounting system that's supposed to track the warheads' every movement (maybe even in real time). We simply don't know how long it would've taken to discover the warheads had they actually left the air force's custody and been diverted into the proverbial "wrong hands." Of course, it could be argued that the probability of this kind of diversion is very low, but anyone who knows anything about how the United States handles its nuclear weapons has said that the probability of what happened at Minot was also essentially zero.
Thus far, the reaction in the United States hasn't been encouraging. The story made a splash in the news, but the public has apparently bought the air force line that there was never a chance of an explosion and that the accident wasn't a big deal. The Pentagon is paying attention (if only because there are still a few people there who remember that nuclear weapons are dangerous), but air force leadership has already started arguing that releasing information about the accident would harm national security by "giv[ing] terrorists insights into how the United States guards and moves weapons." There might be some congressional action, but with the Iraq War taking center stage this fall, it's quite possible that the accident won't get the attention it deserves.
As early comments from knowledgeable people suggest, part of the problem is that the U.S. military no longer takes nuclear weapons seriously--and certainly not as seriously as they took nuclear weapons during the Cold War. I've long argued that in theory this is the right attitude: Indeed, in today's world, nuclear weapons contain no value, rendering them useless and dangerous. But this attitude hasn't translated into bold steps toward radically reducing the U.S. arsenal. The U.S. military, correctly judging that nuclear missions don't give them clout anymore, are trying to come up with different ways to give their nuclear systems some kind of "useful" conventional capability. With no political decision to cut the nuclear weapons forthcoming, they remain in place, sometimes dangerously side-by-side with conventional weapons, hidden from public scrutiny, and increasingly neglected. As the Minot accident demonstrated, this is an accident waiting to happen.
Maybe it's time for the United States to ask itself whether it can handle its nuclear weapons in a safe and secure manner.