Threat from Nagaland

India's 1,300-mile Himalayan frontier with China is one of the world's most unlikely battlegrounds. Monsoon rains flood its approaches in summer, and snows blanket its jagged peaks and passes in winter. All year round, the thin air gnaws at the lungs and vitality of human trespassers in the fastness. Across the forbidding landscape, some 125,000 to 150,000 Chinese troops and more than 300,000 Indian jawans (infantrymen) are positioned in edgy, continuous confrontation.

Since the Chinese invaded India through the passes in 1962, the border has been comparatively quiet. The most recent major firefight occurred last September. At such strategic spots as the 14,140-ft. Natu Pass, linking the Indian protectorate of Sikkim to Chinese-held Tibet, the two sides are literally at bayonet point, patrolling within sight and sound of each other on opposite sides of a single strand of wire. Asian-style politesse prevails in the low-key propaganda war at Natu Pass. Indian loudspeakers kick off daily with news and propaganda in Mandarin Chinese at 5:30 a.m. The Chinese speakers reply in somewhat stilted classical Hindi, which most jawans do not understand, from 6:30 to 11. Then the Indians resume until 1:30 p.m., when both sides fall silent for the rest of the day. Neither side interrupts the other.

End Run in the Hills. Despite the quiet on the central Himalayan front, India has good reason to believe that Peking is attempting an end run on India's defenses in the Naga Hills at the eastern end of the border. The Naga tribesmen who live there have been demanding their own nation for 21 years and are thus receptive to arms, aid and instruction in guerrilla warfare. Mao Tse-tung, true to his own policy of supporting "wars of national liberation," has lately taken to supplying the arts and tools of subversion to the Nagas.

India gave Nagaland official status as its 16th state in 1963, but many of the 400,000 Nagas still want nothing less than full independence. The Nagas are racially distinct from Indians, tracing their Oriental origins to Tibet and Burma. Once ferocious headhunters, many Nagas are now Christianized but have scant brotherly love for Hindu administration from New Delhi.

For eight years Naga nationalists fought an inconclusive war with their Indian masters before agreeing to a cease-fire in 1964. That uneasy truce has recently been renewed for shorter periods. The current cease-fire expires on Oct. 1, and this time, thanks to the new factor of Chinese support, there may be no extension.

More than 1,000 Nagas are known to have trekked 300 miles through Burma to China's Yunnan province for arms, indoctrination and training. Another 1,000 have been intercepted by Indian troops and turned back. Friendly Nagas in Burma sometimes aid the would-be rebels in traveling to China, but others have beheaded at least three Naga rebels and presented their severed heads to Indian officials as signs of good will. Some 300 China-trained Nagas have already returned to Nagaland, and the rest are due to infiltrate back by November.