GIVEN the problem, it seemed a reasonable solution. The north-eastern state of Assam is among the most ethnically, linguistically, religiously and topographically mixed bits of India. It is also the most combustible. In the 1970s and 1980s thousands died in unrest, mostly (but by no means entirely) sparked by fears of the biggest group, Assamese-speaking Hindus, of being swamped by an influx of Bengali-speakers. An impoverished country, Bangladesh, had sprung up next door in 1971, pushing both persecuted Hindus and Muslim migrants over a border so porous that 162 bubbles of foreign territory, some no bigger than a few rice paddies, had been left trapped on either side. So why not, the state’s leaders suggested in 2005, do a tally to sort out Assam natives from recent intruders, and send anyone who came after 1971 packing?

Fast-forward to July 30th, when the state government released a draft of its National Register of Citizens. The much-delayed count, undertaken in earnest only in the past three years, suggests that some 4m out of the state’s 33m people, most of whom are Bengali-speaking Muslims, have failed to prove they are pukka Assamese. The prospect of so many being made stateless, and possibly expelled, has understandably aroused a furore.

Opposition politicians decry the exercise. They say the ruling Bharatiya Janata Party (BJP, which reigns in Assam as well as in Delhi, India’s capital) has cynically designed it to rally its Hindu-nationalist base in advance of next year’s general election. Mamata Banerjee, chief minister of neighbouring West Bengal state, warns of “a civil war, a bloodbath”. While cooler heads in the BJP note that the count was started under previous governments, hotter ones accuse the opposition of being unpatriotic and playing “vote-bank politics” with Muslims, who make up over a third of Assam’s population. One BJP legislator from far-off southern India declared that if Bangladeshi or Rohingya immigrants (the latter fleeing persecution in Myanmar) do not leave, they should be shot.

Assam remains calm, for now. Local leaders insist the register is just a draft, and that anyone may challenge their status. As it is, many have spent weeks and months, as well as fortunes in legal fees, to dig up the dusty old documents needed to prove ancestral links to the state—if these even exist. Those left off the current list include officers in the Indian army, one from a pair of twins, tens of thousands of women from families too poor, unlettered or conservative to have considered registering their births or marriages, and several serving or former members of Assam’s local legislature—including one from the BJP.