One of the points I made (which is not original to me) is that in modern warfare, the real target of attack is not the opposing military -- it is the will and capacity of states to make war.
Similarly, the real target of weapons of mass destruction is not the victims, but the survivors.
A useful way to look at this is to consider WMD to stand not only for destruction, but equally for disruption.
And if you think about it even further, you can see that WMDs are more than just weapons; in fact, they comprise whole systems.
I've broken down these systems of mass disruption into four distinct components:
- Payloads
- Modes of delivery
- Methods of targeting
- Means of production
So, how will advanced nanotechology affect these SMDs?
First, "signatures" of WMD will be reduced at the same time as payloads are increased. We could see much smaller signatures -- nearly vanishing -- and far more destruction, thanks to nanotechnology.
In place of nuclear, chemical, or biological warheads, huge numbers of simple, low-tech, but still highly damaging devices could be produced. You might think of them as the equivalent of the Molotov cocktail, but delivered simultaneously by the millions to precision targets.
Nothing more exotic than that is needed to create mass destruction and mass disruption. Such weapons could be made cheaply, in nearly unlimited numbers, and with almost no detectable signature unless nanofactory technology is effectively regulated.
Modes of delivery -- whether they are UAVs (unmanned aerial vehicles), armies of small robotic crawlers, or space-based -- will be equally inexpensive to produce and deploy in vast quantities. Ubiquitous sensors for surveillance, target tracking, and weapons control, enabled by low-cost supercomputing and also produced by molecular manufacturing, will greatly enhance methods of targeting.
Of the four components I mentioned, the most important and potentially most disruptive is the last: means of production. Advances might be made in the other three areas without reliance on nanofactory technology, but they will have relatively limited impact by comparison. However, when we reach the point that an atomically-precise general-purpose manufacturing system can be reproduced exponentially, then systems of mass disruption will take on a whole new meaning.