It's an interesting paper but "politically stable" isn't the right term. A population able to defeat the infantry technology of the time requires a different s

It's an interesting paper but "politically stable" isn't the right term. A population able to defeat the infantry technology of the time requires a different social and legal position than one that doesn't have that ability. That is, the government needs more cooperation and consent of the governed. That government is stronger than other governments, because it can kill their armies. But it is more dependent on that population and so cannot abuse it in the same manner as those other, "weaker" governments.