ON JULY 6th, a month after an altercation at a mosque in a region run by (non-Muslim) tribesmen in north-east India, four men on motorcycles shot and killed two Muslims. Six weeks later, some 80 people have been killed in communal bloodletting; the army has been sent into Assam with orders to shoot to kill; tens of thousands of north-easterners in other parts of India have fled homeward in fear of their lives; India has accused Pakistanis of being the origin of doctored video messages designed to stir up religious hatred; and 400,000-500,000 Indians are homeless or displaced within Assam, the largest involuntary movement of people inside the country since independence. How on earth did a local conflict, one of many in the area, produce such devastating nationwide consequences?

The spark for the extraordinary sequence of events was a fight in western Assam between indigenous Bodo tribesmen (pronounced Boro) and Bengali-speakers who have been moving into the area for more than a century. The Bodo say the incomers are illegal immigrants from Bangladesh and want them to be kicked out.

The migrants are mostly Muslim. The Bodo are animist or Christian. Muslims have grown modestly as a share of Assam’s population (from 24% to 31% in the three decades to 2001). No surge explains the latest violence, although the Muslim population of western Assam is growing faster. In some villages the Bodo are now a minority. They say they feel swamped by Muslim immigrants.

However, the conflict is not primarily about religion. It is about land. The Bodo hold land in common. The Bengali-speakers are settled farmers, anxious to establish private-property rights as protection against dispossession. In 2003, after a long, violent campaign for autonomy, the Bodo got their own Bodo Territorial Council, on whose turf outsiders may not own property. The Bodo consider all Muslims outsiders—hence the dispute at the mosque.

Assam’s conflict has been going on for decades. A massacre in 1983 was far more brutal than this year’s violence. Yet until now the dispute, like other insurgencies of the north-east, has had no real impact elsewhere in the country.

This time, there were riots in Mumbai and attacks in nearby Pune on people from Manipur. Some 30,000 north-easterners fled from Bangalore, nine of them being thrown off a moving train. Some authorities encouraged the exodus by laying on special trains: 30,000 tickets to Guwahati, Assam’s capital, were sold in three days. The impact of mobile phones has made a difference. On August 12th people started getting text messages warning north-easterners to go home before the end of Ramadan (August 20th). They also got video messages with doctored images purporting to show the bodies of Muslims killed in Assam. In fact these were victims of Cyclone Nargis in 2008 in Myanmar. India’s home minister, Sushil Kumar Shinde, said that many of the fake images came from websites in Pakistan and asked for the Pakistani government’s help in closing them down. Pakistan denied involvement. India ordered the blocking of over 250 websites and asked mobile-service providers to restrict the number of SMS messages. Yet the images have gone viral. The Assam conflict also spread because people elsewhere sought to capitalise on it. Mumbai saw rival protests by a big Muslim organisation, the Raza Academy, then a big Hindu one, the Maharashtra Navnirman Sena. The opposition (Hindu-nationalist) Bharatiya Janata Party said Assam’s problem is illegal immigration from Bangladesh. Assam is ruled by the Congress party. Its chief minister, Tarun Gogoi, said bluntly “there are no Bangladeshis in the clash but Indian citizens.” The Assam conflict has not been such partisan fodder before.

The reverberations across the rest of the country may force Indians to focus for once on the chronic failings of government policy in the north-east. Linked to the rest of the country only by a “chicken’s neck” stretch of land 22km wide, the region is isolated, poor and different. Assam, easily its biggest state, is one of India’s poorest. North-easterners look different: a Manipuri teacher in Pune says everyone from passers-by to his pupils calls him, offensively, “Chinky”. North-easterners call the rest of the country “mainland India”.

One manifestation of this distinctiveness is the persistence of insurgencies. The Institute for Conflict Management, a think-tank, lists 26 active armed groups in the region, and ten organisations proscribed by India’s home ministry. There are armed separatists in five of the seven states. In the early 2000s the death toll was 1,700 a year.

Dealing with such a region was always going to be hard. Yet successive governments have made things worse. They have attempted to placate insurgent groups by giving them more autonomy. The north-east has 16 such areas, more than the rest of India. But giving each group a place of its own creates restive new minorities within the area—as in Bodoland.

National politicians have also shied away from dealing with illegal migration, partly because the issue is toxic and partly because local politicians like to register newcomers as voters. For a while, Assam even had its own immigration policy, until that was struck down by the Supreme Court. By letting ambiguity about incomers’ legal status persist, politicians leave the field open to armed extremists who want to kick all Muslims out.

Central governments have attempted to buy peace. Between 20% and 55% of north-eastern states’ GDP comes in transfers from the centre—a huge proportion. It keeps their economies going, but turns local governments into client states surrounded by autonomous areas ruled by former insurgents, while armed gangs wage guerrilla campaigns at the margins.

It is fair to say there have been some improvements. Fatalities have fallen since 2008, thanks to a deal with Bangladesh which denied some insurgents their former bases. But as is clear from the Bodo conflict, the grievances which produced the insurgencies remain. India’s long-term goals in the region are to encourage its integration with the rest of the country, to use the north-east to boost economic ties with South-East Asia, and to check China’s influence in Myanmar. At the moment, none of those aims is being advanced.