There are three facts worth remembering about the Lindsay Clancy trial before getting lost in all the debates surrounding it: Cora Clancy was five years old, Dawson was three and Callan was eight months. All three were strangled by their mother.

The question before a Massachusetts jury is not whether Lindsay Clancy killed her children: her defence does not dispute that. Her lawyer has said explicitly that he is not contesting the prosecution’s basic case that she strangled each child with exercise bands in the basement of the family home. The argument is instead that Clancy was suffering from postpartum psychosis and was therefore not criminally responsible for what she did. As I write, the jury is deliberating. Mental illness can diminish moral responsibility and, in extreme circumstances, perhaps remove it altogether. The Catholic Church has always recognised this. The Catechism says that responsibility may be “diminished or even nullified” by psychological factors.