You don’t have to be Steven Pinker to notice a stark contrast: Despite our gloomy attitudes and “if it bleeds, it leads” news media, we live in a time of relative peace and prosperity. There is less violence (violent crime as well as war) than ever.

And despite our bellicose political rhetoric, this may be especially true when it comes to politics. “Between 1830 and 1860,” writes Yale professor Joanne B. Freeman in her book The Field of Blood, “there were more than seventy violent incidents between congressmen in the House and Senate chambers or on nearby streets and dueling grounds.”

That, of course, was just before Abraham Lincoln was killed.