I started to read his 2011 book 'Better Angels of our Nature: Why Violence has Declined'
It is a long (800+ pages), but provocative book. From what I gather so far, he is saying that violence has been declining since the beginning of human history. He splits human history into periods and says that we are in the most peaceful time in history. and violence is being discredited. He even has graphs that show that hunter-gatherer or 'anarchist' societies had much higher murder rates, when you look at proportions (murders per 100,000 people). With around 25 percent of people dying from violence in the medieval period. And around 300-500 per 100,000 occuring in the renaissance and around 1-8 per 100,000 today. With western europe being around 1 per 100,000 for about a century.
But he also gives five reasons, some of which we might agree with, others we won't.
The Leviathan (the state; reigns in internal violence)
Gentle Commerce (economic incentives for cooperation)
Feminization (empowerment of women; men are naturally more violent)
The Expanding Circle (empathy; sympathizing with ever wider classes)
The Escalator of Reason (rationality; application of empathy)
and distinct periods in the history of violence:
Anarchic hunter-gatherer
Civilizing process
Humanitarian Revolution and Enlightenment
Long Peace, since WW2
New Peace, since the Cold War
And the relatively recent 'Rights Revolution': opposition to bullying, discrimination, beating women and children, etc. among many or most people.
He says that Leviathan is one of the main reasons for the decline of violence. And violence which still exists occurs because the police and criminals do not really identify or see much use for the other. Which occurs in some parts of America, usually with white cops who police black civilians, where the civilian does not feel confident that he/she can appeal to the state. But when the confidence rises, in other parts, this is usually creates more peace. Hence some parts of the US are comparable to the peaceful Europe. While others are incredibly high.
He also takes on some arguments about human nature. Claiming that Hobbes and Roussaeu were both wrong about many things, since they had no empirical data. He refutes some beliefs about human nature, while making some evolutionary arguments for what might be more correct. For instance, if we are capable of constant warfare like our ancestors the chimps. Or more peaceful like the bonobos. Scientists do not know which way early humans lived. Or if indeed we actually know the true lifestyle of bonobos, given their endangered and controlled status. native americans today, also lived in a controlled environment instead of lush environments, and there is no way to know much about their distant history. He also looks at some archaelogical data to see signs of violence.
I think this is an interesting, albeit long, contribution to the discussion of states versus anarchism. With Pinker taking the side of states, in this case. But with well-documented facts. This might be one of the most popular political books right now. So it is definitely worth discussing.