In theory, Pakistan is a country that welcomes all creeds and castes. But in practice it is proving to be anything but. Ask Faryal Bhatti, a teenage girl recently expelled from school for the crime of bad spelling.

A week ago last Thursday, the 13-year-old Christian girl was sitting an Urdu exam which involved a poem about the prophet Muhammad when she dropped a dot on the Urdu word naat (a devotional hymn to the prophet), accidentally turning it into lanaat, or damnation. Spotting the error, her teacher scolded her, beat her and reported the matter to the principal. The news soon flamed through her community in Havelian, 30 miles north of Islamabad.

Mullahs raged against Bhatti in their sermons; a school inquiry was hastily convened to examine the matter. Bhatti was expelled; her mother, a government nurse, was banished to another town, and the family has since fled Havelian in fear of their lives. All over a missing dot.

What accounts for such madness? In some parts Taseer’s death has inspired a McCarthyite atmosphere in which nobody wants to seen to be soft on blasphemy. But there is also a more profound reason. Devotion to the prophet Muhammad is central to the faith of the Barelvi Sunnis, who make up the majority of Pakistani Muslims. Even a whiff of insult to the prophet can whip up feverish anger.

The core problem, in fact, is that the blasphemy furore exposes the fragility of the Pakistani state – ideological, legal and security-wise. The mixing of religion and politics has long troubled Pakistan, but over the past 30 years that dangerous cocktail has been spiked by the army’s policy of nurturing extremists – hence men like Qadri who believe they have a right to kill in the name of God.

Meanwhile President Asif Ali Zardari’s government has shown zero leadership when it comes to reforming the blasphemy law – in fact, cowardly ministers have run a mile from any suggestion of change. And those who do dare to stand up for progress – or just the rule of law – live in fear of the next Qadri-style hit.