Ayaan Hirsi Ali, the controversial Muslim-turned-atheist, told a National Press Club audience last week some hard facts about Islam and its propensity toward violence. But her remarks about Christianity—about its capacity to soften sectarian hatreds—may prove an even tougher pill to swallow.

The New York Times best-selling author is promoting her latest book, Heretic: Why Islam Needs a Reformation Now. For over a decade, Hirsi Ali has argued that Islam is not a religion of peace and tolerance. Although Islamic belief does not make Muslims naturally violent, she says, the call for violence is explicitly justified in the sacred texts of Islam. “This theologically sanctioned violence is there to be activated by any number of offenses,” she writes, “including but not limited to apostasy, adultery, blasphemy, and even something as vague as threats to family honor or to the honor of Islam itself.”