In discussions of the San Bernardino massacre, investigators want to determine at what point, exactly, the killers became “radicalized.” This inappropriate word makes it sound as if the perpetrators developed a disease, or fell under some evil spell – minimizing the extent to which their hideous crimes constituted a series of personal choices.

“Radicalization” doesn’t just happen – and it’s not always a discernible process. But it is worth noting that for Muslim terrorists, it always seems to involve an increase in religiosity. Many observers saw the San Bernardino couple becoming more devout which, in an Islamic context, can be a real danger. Muslim Americans should reform their faith to root out this unique susceptibility to terrorism: no one would worry that a Christian who attended Bible study more regularly or a Jew committing to daily prayer might suddenly become a violent extremist. In today’s world, Muslims have too often expressed religious fervor by supporting or perpetrating mass killing.