The potential benefits of molecular manufacturing (MM) are immense. Ironically, this will create at least two problems. There is, of course, the moral issue of ensuring that new benefits and possibilities are not denied to the world's citizens. There is also the problem that repression or prevention of MM, unless carried to hideous extremes of oppression, would simply attract a criminal element to supply the denied benefits through a black market. This in turn would make policing harder, leading to more restrictions and more incentive for crime.
The cycle between oppression and crime is one of several vicious cycles that could be induced and fueled by molecular manufacturing, but must be avoided. A technology that can quickly make billions of lethal unmanned aerial vehicles (UAV's) the size of a small hummingbird for a few thousand dollars — total, not apiece — will create problems that cannot be solved by any simple solution. MM will impact security, economics, and information flow, each of which requires very different policy approaches. Bad policy in one area may create far worse problems in another area; bad policies will not cancel each other, but will each make the situation worse.
All of these reasons point to the urgent need for learning, as soon as possible, the earliest date by which molecular manufacturing plausibly could arrive.