I think the possibilities are amazing but things will end up for the worse. They'll spur technology farther, the NSA, FBI, will have microphones in every house, our heads will receive cell phone signals with just a tiny drop in our ear, TVs will be available on our eyewear (complete with cable) and car accidents will rise because some bozo is watching ESPN, their will be bio-enhancers that spark neural synapses but eventual use will send users into a vegetative state, our bodies will break down due to foreign matter invading our systems, they will hunt down organisms and bacteria at an atomic scale effectively wiping out crops, their will be famine, we'll die and cockroaches will out live us.
"I never saw a miracle of science that didn't turn from a blessing into a curse." -Sting
The Nixon administration considered the use of nuclear weapons in the Vietnam War on the Vietcong.
For anyone reading this - consider this question: Why weren't they used?
Outside of all the moral and ethical conundrums - one reason they weren't used is that they couldn't be used secretly. The world would know.
Then - and now - nuclear weapons are the single most destructive weapons that exist.
That will change. Nanotechnology will redefine what a "weapon" is. It is a technology that presents a multitude of dangers.
Governments have show a willingness to use any weapon available to them on a despised enemy. This being the case the abuse or misuse of nanotechnology is chilling.
It could be weaponized and used as a "virus" to infect the enemy with nano, biological or chemical agents. It could be the first "weapon" in history to self-replicate in an (ideally) controlled fashion.
It could be used with a degree of secrecy unknown at the present time.
I think a politician (of a country that has them) will - at one point - be unable to resist using them. It's a politician's and military planners' dream war - massive causalities for the enemy - with (ideally) none for their side.
An immoral leader could use them to "neutralize" not just soldiers but a city or a region. The target area could have catastrophic causalities.
Needless to say - a multitude of things could go wrong. A situation were a self-replicating weapon "breaks free" is like something out of cheesy 1950s sci-fi.
But it's not funny now. Such dangers will exist.
And, of course, weaponized nanotechnology could be used by terrorists.
nanotechnology can be very beneficial to us. imagine having little transformers swimming through our veins providing backup for our white blood cells.
but i think its good and natural for us to fear it. the rate that technology develops is much faster than we as a human race know what to do with it. soon the human brain will be obsolite and it will be nescessary for people to "upgrade" to survive!