The website Concurring Opinions hosted a symposium on a book by Susanna Blumenthal, Law and the Modern Mind. I reviewed Blumenthal's book for The Federal Lawyer, b ut surprisingly was not asked to contribute to the symposium. At any rate, I find some of the material gathered for this purpose intriguing. In her reply to one of her critics, Blumenthal includes this thought: I have long been fascinated with the theatricality of insanity trials and the extent to which they doubled as entertainment forms in nineteenth-century America, bearing a certain resemblance to the commercial amusements of P.T. Barnum, who created controversies about his own exhibits, advertising that experts disagreed about their authenticity and democratically inviting “the sagacious public” to decide for themselves. This passage reminds me that James Holmes, the fellow who in 2012 dressed up as The Joker and shot up a movie theatre in Colorado, killing 12 people. Holmes' trial in 2014 was the...