Ultimately this just goes to show that monitoring, inspections and intelligence will eventually fail us. The root of our problem isn't that countries are trying to obtain nuclear weapons. It's that the countries in question are unstable tyrannies with ties to terrorism and emnity towards the US. No one cares how many bombs France has.
The danger of containment and inspection is that we are only treating symptoms. Unless we cure the disease and change these regimes at their core, we will eventually miss something or fail to act, and we'll pay the price of our negligence with something that makes 9/11 seem like a pleasant memory.