Rik van Riel wrote:
> Why? We've all seen that in the cold war there were 'enough'
> weapons to ensure mutual destruction. With nanotech that point
> will be reached much earlier and the 'enough' will be even
> more extreme. After that there shouldn't be any incentive to
> build more weapons (since there's no need for more).
This is only true in the opening phase of the arms race, when human civilization looks is spread across the surface of the planet and you your ability to replace people with hardware is severely limited. Things get a lot worse after that point.
As nanotech and AI become more advanced the military forces of a nation become more and more resistant to both nuclear attacks and indiscriminate green goo. They can build deeply buried manufacturing facilities, build combat robots with heavy radiation shielding and robust nanotech immune systems, and move all military personnel into armored bunkers. As the bunkers get deeper and the robots get tougher most world powers will respond by building bigger nukes, more virulent goo, and more and more sophisticated robotic armies.
There are several unfortunate trends here. The first is that the survivability of military forces tends to increase over time, because burying yourself under a mountain is easier than moving one. As a result the chance of nuclear weapons being used actually increases, which is a shame because the environment and civilian population on the surface are still very fragile targets. There is also a strong incentive to build very large robotic armies, because a) you can't destroy one with cheap weapons of mass destruction, and b) other things being equal, big armies tend to beat smaller ones. I don't see the incentives changing until someone invents a new super weapon capable of physically disrupting the entire volume of a planet, or until all of the Earth's mass has been converted into an optimal mix of shielding, weapons and industry.
Now, I would hope that we'll see a significant migration into space long before then. Spreading across the solar system would help because it would make it much easier to defend a civilian population, since any attacking force must cross a large amount of open space where it can be detected with relative ease. Interstellar colonization would be even better, because it would make the time required to launch an attack comparable to the time required to build a navy capable of stopping it.
Mind you, all of this only applies to civilizations that are not yet doing mega-scale engineering. Once you start remodeling entire solar systems the whole dynamic would change yet again, and I'm not sure what the result would be.
Billy Brown, MCSE+I