There seems to be a bit of national security camaraderie in the Nuclear Club. The United States, in the early years, worked out a number of procedures, like the two-man rule and emergency action messages (EAMs) to make the control and handling of nuclear weapons safer (presumably for the issuer, not the receiver). But alas, various events over the era of the Cold War showed that even the best of intentions are usually insufficient to overcome a really determined foe, especially if it’s your own military. This entire set of procedures was generated to insure that nuclear weapon release was under civilian control. In at least one instance, launch codes, established to insure that the National Command Authority was the only authority able to release weapons, were set to 00000000 for extended periods of time. The military did this because they were concerned that release authority would not be granted expeditiously in a real crisis.
So clever people got together and developed some clever techniques. Buried deep within US nuclear weapons is a system that enables “a significant yield”. Which essentially means that, yes—you can blow up the warhead, but without the system enabled, you can’t get a nuclear yield. At best you get a small explosion (and a lot of radioactive debris blown all over). This system is called a PAL or permissive action link. Its operation involves cryptology and interesting tricks to insure that a significant nuclear yield cannot occur unless NCA has authorized release.
Now the really interesting part is that when the Soviet Union clearly demonstrated that they were capable of designing and exploding nuclear and thermonuclear weapons, the United States designers met with and offered their USSR pals information as to how these things worked so that each country would have a high confidence that the warheads were under civilian control and that release could not be compromised. Similarly with the other Club members.
So the argument might apply to Iran, who seems actively engaged in developing such a weapon. Should the US or other countries exchange these techniques with Mahmoud Ahmadinejad? The answer is a resounding NO! No PALs for our pal Mahmoud. First of all, assuming that Iran does in fact develop a viable weapon, who is likely to control that weapon? (The Mullahs would be the equivalent of civilian control). The Iranian Revolutionary Guard will likely be tasked with actual release coordination. But one may ask — who is it that the Mullahs are most likely to fear? Aside from the usual suspect, it is the Iranian people. And anything the US can do to enable the Iranian people against the ruling regime should be considered. Let the Mullahs find out that owning weapons in Iran is like having a glass house with a $100,000 stereo system in Chicago’s south side. Maybe having a nuclear weapon will turn out to be a nice sharp two edge sword that keeps them looking inwards. So the US should only consider this technology transfer AFTER a intercontinental delivery system is developed . Until then the greatest threat of Iran’s nuclear weapons system will be to itself.