I don't know if it's an existential risk, but if technology keeps enabling fewer and fewer people to kill more and more people for less and less money (hint: it will)

Do you see any clear linear increase in bodies per attacker in that database?

In the very long-run there's going to be a problem that if the trends keep continuing it will be possible for single crazy people to do nearly indefinite levels of damage. That's a problem whether the individuals are motivated by religion, ideology, or are just wacko. Charlie Stross in one set of novels imagined a world where there's a real problem that every crazy person can build their own nuclear weapon, but I don't think he took it to its logical conclusion. The solution here may be simply to spread out so much to other planets that isolated incidents cannot do enough damage.

No. In 50 years it will probably be possible for the U.S. to have total drone surveillance of a country. We could assign everyone their own drone that monitors their behavior and alerts us if they do something we don't like. And even if this proves not to be the case, rather than resort to genocide couldn't we just cut off electricity to dangerous areas?

I don't know if it's an existential risk, but if technology keeps enabling fewer and fewer people to kill more and more people for less and less money (hint: it will), and Islamic countries continue to produce as many people who want to kill us as they do now, then at some point, perhaps 50 years from now, "we" will have to kill everyone in every country where radical Islam has a hold. (That's about 400 million people at present.)

Hey guys, defection has gotten really easy... screw cooperation, let's start defecting all over the place!