BHANUPRATAPUR FOREST RESERVE, India — The gray light of dawn broke over the bamboo forest as the People's Liberation Guerrilla Army prepared for a new day. With transistor radios tucked under their arms, the soldiers listened to the morning news and brushed their teeth. A few young recruits busied themselves making a remote-control detonator for explosives. The company commander, Gopanna Markam, patiently shaved. "We have made the people aware of how to change your life through armed struggle, not the ballot," said Mr. Markam, who is in his mid-40's, describing his troops' accomplishments. "This is a people's war, a protracted people's war." Mr. Markam's ragtag forces, who hew to Mao's script for a peasant revolution, fought a seemingly lost cause for so long, they were barely taken seriously beyond India's desperately wanting forest belt. But not anymore. Today the fighting that Mr. Markam has quietly nurtured for 25 years looks incr...