If you can assume the worst about dragnet surveillance - NSA has already done it. That would be a pretty safe bet at this point.
Now, computers can track the development of that nemesis for nearly free. If the situation develops the global network of finance can be made to exert pressure on the undesirable. Then, if the situation continues to develop, near perfect information can be used to find a law that they broke and arrest them.
We see out country using lethal force in the only situations that benefit it, namely armed confrontations or societies outside the reach of our financial and political power.
Remember the criteria for that? If there is a suspect, not convicted, but merely a suspect, its simply collateral damage if you also wipe out his wife and kids, oh, and family... and friends..... by standers. No due process.
Or did you mean Americans?
Well, even if you did, I have to wonder how long it will take for drones to be , er, surgically taking out drug dealers in shitty areas in the US. For the sake of the children, you understand.
These actions are definitely a step along the slippery slope of legitimizing other practices. Plus, it is entirely possible that our intelligence agencies have already targeted some individuals very specifically for neutralization somehow. We can only confirm that they have not done so through transparency and oversight.