Here are extracts from the essay, though it should really be read in its entirety:
"Until the 1990s the Naxalites were a marginal presence in Indian politics. But in that decade they began working more closely with the tribal communities of the Indian heartland. About 80 million Indians are officially recognized as "tribal"; of these, some 15 million live in the northeast, in regions untouched by Hindu influence. It is among the 65 million tribals of the heartland that the Maoists have found a most receptive audience.
... ... This twin marginalization [of tribals], economic and political, has opened a space for the Maoists to work in. Their most impressive gains have been in tribal districts, where they have shrewdly stoked discontent with the state to win people to their side. They have organized tribals to demand better wages from the forest department, killed or beaten up policemen alleged to have intimidated tribals and run law courts and irrigation schemes of their own.
... ... ...How many Maoists are there in India? Estimates vary widely. There are perhaps 10,000 to 20,000 full-time guerrillas, each armed with an AK-47, most of them conversant with the use of grenades, many with landmines, a few with rocket launchers. They maintain links with guerrilla movements in other parts of South Asia, exchanging information and technology with the Liberation Tigers of Tamil Eelam and, at least before their recent conversion, the Nepali Maoists.
The Indian Maoists got a huge shot in the arm with the merger, in 2004, of two major factions. One, the People's War Group, was active in Andhra Pradesh; the other, the Maoist Co-ordination Committee, in Bihar. Both dissolved themselves into the new Communist Party of India (Maoist). Since the merger the party has spread rapidly, with former PWG cadres moving north into the tribal heartland from Andhra, and erstwhile MCC cadres coming south from Bihar.
My guess is that about forty districts, spread across ten states and containing perhaps 80 million Indians, live in a liminal zone where the Indian state exercises uncertain control by day and no control by night. Some of these districts are in the northeast, where the nighttime rulers are the Naga, Assamese and Manipuri rebels. The other districts are in the peninsula, where Naxalites have dug deep roots among low castes and tribals grievously shortchanged by the democratic system.