Sir Henry McMahon, then the foreign secretary of the British-run Government of India, was responsible for drawing up the official border between British India and China. This denied China the right of ruling Tibet. McMahon was a treacherous negotiator: he presented a different map than the one in the Simla Agreement of 1914 to the Chinese, thus washing British hands of the negotiated border. He was sent back to London in disgrace, but 30 years later, the McMahon Line became the cartographic border between British India and China.
After Independence, India inherited all British territorial agreements, including the McMahon Line. In 1954, during border talks with India’s northern neighbour, Jawaharlal Nehru refused to yield to the Chinese over Tibet saying “the McMahon line marked their border with China, where was the need?” China was not in agreement over the negotiations between Tibet and Britain. Nehru couldn’t come to an agreement with the Chinese on negotiating a border acceptable to both parties. The Indo-China border became the LAC (line of actual control); the point up to which each nation was capable of administering their territory. After the Chinese occupied Tibet in 1950, India was initially supportive, even recognising Tibet as part of China.
The Indian Army, meanwhile, took control of Tawang in NEFA, driving out Tibetans. In 1954, India acknowledged Chinese sovereignty in Tibet after the Panchsheel Accord with China. But by 1951, China had already constructed numerous army posts in Aksai Chin. China became wary that India had allowed the CIA to set up training camps for Tibetans fighting the Chinese. In 1958, India protested to China that it had built a road between Xinjiang and Tibet through Indian territory in Aksai Chin, Ladakh. Nehru refused to accept Chinese claims over Aksai Chin, in return for China giving up claims on Indian territory in NEFA.
Chinese premier Zhou en Lai visited India four times to convince Nehru, but did not succeed. The Chinese were furious at India giving the Dalai Lama asylum in 1959. In 1961, Chinese soldiers started patrolling the McMahon Line, crossing over to Indian areas, which angered India. Sardar Patel, then the Home Minister, declared on February 4, 1962 that “if the Chinese will not vacate the areas occupied by her, India will have to repeat what she did in Goa. She will certainly drive out the Chinese forces.”
India constructed 60 Army forward outposts, including 43 north of the McMahon Line. This was called the ‘Forward Policy’, which strategically flanked Chinese military positions to assert Indian territorial claims in Ladakh. Both countries questioned each other’s territorial claim, and India opposed Chinese claims over Tibet. A free Tibet was essential for maintaining India’s security. On October 20, 1962, the People’s Liberation Army (PLA) of China crossed into Ladakh and across the McMahon Line, capturing Rezang la and Tawang before declaring a ceasefire on November 20, 1962.