THIS morning I read of the altercation in Montana that led a homeowner to shoot and kill a jealous husband. Brice Harper had a relationship with Dan Fredenberg's wife. The wife insisted it was only an "emotional" affair, but no mind: an angry, intoxicated and unarmed Fredenberg charged into Mr Harper's Montana garage, where Mr Harper shot him dead. The Kalispell, Montana police are not charging Mr Harper with any crime. The reason is the "castle doctrine", newly added to Montana law. If someone has merely "reasonable belief" that he will be assaulted, even by an unarmed assailant, in his home, he may use deadly force in response. The traditional arguments quickly flow from both sides: from the police and gun-control advocates, that this is a "license to kill", from the pro-gun lobby, that it deters crime. What struck me was not the usual arguments, but the word "castle" attached to the legal doctrine in question. As it happens, last night I was reading Steven Pinker's "Better Angels of Our Nature". As those who have heard of the book know, Mr Pinker argues that violence (both war and homicide, and assault to boot) have declined precipitously in almost all corners of the world. He sets out to explain why. Critics of the book have completely failed, in my view, to rebut Mr Pinker's masses of evidence that violence has, in fact, declined. But his "why" is interesting, and controversial. In "The Pacification Process" (Chapter 2), Mr Pinker argues that the growth of modern states—Hobbes's "Leviathan"—allowed people to put violence in the hands of the sovereign and escape the "security trap" that made them feel that they had to fight on a hair-trigger to protect themselves from potential threats. (When everyone is on a hair-trigger, the whole society is violent.) As those sovereigns grew in reach, homicide declined dramatically. In "The Civilizing Process" (Chapter 3), he argues that this gradually led to an ethic of self-restraint in the societies lucky enough to have an effective sovereign. All manner of urges—to have sex, fight, spit, urinate, you name it—became things that "civilised" people (first in the upper classes, then gradually the middle and lower classes) were expected to control. As late as the mid-1800s, an English gentleman was expected to beat a boorish cabman or bargee for an affront we would now consider trivial.

The path is from non-state societies (homicide rates around 100 per 100,000) to medieval proto-state societies (tens per 100,000) to early modern society (high-single digits per 100,000) to peaceful modern Europe (around 1 per 100,000), roughly an order-of-magnitude drop each time. So what word do we reach for when we want to name a doctrine allowing a man to kill another man for crossing his property line with a certain look in his eye? No modern metaphor will do; a literally medieval one must be retrieved. A man's home is his castle.

Murder rates are about four times higher in America than in western Europe. And guns are not the only reason; murder by stabbing and clubbing is higher, too. The murder rate is higher among blacks, but American whites are more violent than European whites. The South is America's most violent region; both blacks and whites in the South are more violent than those in the northeast. In other words, the murder rate is highest in those states that most disdain the sovereign ("government") and champion self-reliance.

Another useful nugget from Mr Pinker's book is a short section on the real occupation of medieval knights. Centuries of myopic re-imagining has them as championing women's honour and fighting in symbolic tournaments. But based on what they actually did, today we would call them warlords. Heavily armoured and armed and on horseback, they led peasant armies against one another, often wreaking their worst violence on the other side's unarmoured peasants. The word "chivalry" has its roots in the knight's battle mount (cheval), not his behaviour towards ladies.

All this is of course not to say America is literally medieval. In a thousand years, it will surely still be considered one of history's most culturally and intellectually fruitful civilisations. But it is also unusually compartmentalised; the country with the world's greatest scientific production also hosts the rich world's biggest share of evolution-denying biblical literalists. And so, similarly, from a European, Canadian or other rich-world-country perspective, American attitudes towards righteous violence are a strange outlier from its civilisation, seemingly belonging to another age, castles and all.

(Photo credit: AFP)

Update: Prof Pinker, by coincidence, weighed in on these topics yesterday in the New York Times, a day after this post went live.