The South Asian subcontinent, by virtue of its geo-strategic location and population, for many years has been a central area of the Great Power struggle for influence. In the course of time, the Cold War rivalry between the two Great Powers percolated down to South Asia. Both the United States and the former Soviet Union have vied with each other for gaining a foothold in the South Asian region. India and Pakistan in the course of their foreign policy utilised the superpowers’ rivalry to their advantage. For example, Pakistan’s willingness to accommodate the American interests not only brought the external power into the subcontinent but also strengthened its confrontationist anti-India stance. Eventually, the Indian act to seek aid from the former Soviet Union brought both the protagonists of the Cold War into the region. The major powers have played a major role in South Asia in its politics as well as in its economic development.

The political stability of South Asia got shaken when the American U–2 spy plane was shot down by the Soviets in May 1960.The plane had reportedly taken off from a Pakistani base. The Soviets constantly issued protest notes to Pakistan that the US air bases in Pakistan had a direct bearing on their security. This increased the Soviet interest in the South Asian region, particularly with India which was less rigid about accepting arms from the Soviet Union after the US arms aid given to Pakistan. The Indo-Soviet relations coincided with the deteriorating Sino-Soviet and Sino-India relations. The Chinese attack on India in 1962, however, placed the USSR in a delicate position as it was difficult for it not to support a Communist state, Hence, Moscow adopted a neutral position. The US, on the other hand, sent twelve C–130 Hercules transport planes with the crews to help India in transporting its men and materials on the mountainous borders.

The arms embargo fell heavily on Pakistan as it was dependent on American supplies. Pakistan felt let down by the US which should have extended help to them as per the assurances given to them when Pakistan joined the South-East Asia Treaty Organisation (SEATO) and Central Treaty Organisation (CENTO). The neutral stand taken by the US during the September 1965 War further infuriated Pakistan as it had expected the US to use its influence to stop the Indian invasion across the international line which threatened Pakistan’s independence.

In order to avoid dependence on one supplier, Pakistan gradually moved towards China. In March 1965, Ayub Khan visited China and secured not only Chou-en-Lai’s assurances of support to Pakistan in the event of an Indian aggression but also military supplies. The interest shown by China in the Indo-Pak subcontinent became a matter of concern to the American policy makers. Therefore, the US lifted the arms embargo partially in 1967 and agreed to sell non-lethal weapons to both India and Pakistan.

During the 1965 War, the Soviet Union adopted a neutral stand and offered its good offices for a peaceful settlement between the two warring states. The Prime Ministers of India and Pakistan met at Tashkent on January 3, 1966.The conference lasted from January 4–10, 1966, at which they agreed to create good relations in accordance with the UN Charter, to promote understanding and friendly relations and a total pull-out of troops before February 25, 1966 to their pre-war positions. Russia emerged as a peace-maker at a time when the US was involved in the Vietnam War.

Fearing that Soviets might get involved in the 1971 Indo-Pak war, then US President Richard Nixon had wanted China to make coordinated military moves in support of Pakistan, according to documents released by the State Department.

The Nixon administration was not prepared to involve itself in a war on the Indian sub-continent. Nor did it pay much attention to Indian concerns about "the carnage in East Pakistan" and the problems of refugees in West Bengal, said a State Department press release giving the gist of the papers on the Bangladesh War of Liberation, released yesterday. But, the signing of the India-Soviet Union Treaty of Peace, Friendship and Cooperation in August 1971, while not a mutual security treaty, was viewed in Washington as a blank check to India in its confrontation with Pakistan.

The US policy included support of Pakistan in UN and pressure on Soviets to discourage India, with hints that US-Soviet detente would be in jeopardy if Moscow did not comply. At Nixon’s instruction, his assistance for National Security Affairs Henry Kissinger met China's ambassador to the UN Huang Hua to suggest that Beijing make coordinated military moves in support of Pakistan. The implication conveyed by Kissinger was that if the soviets responded militarily, the US would support China in any confrontation with Soviet Union. When the Chinese asked to meet Kissinger in New York two days later, the White House assumed the worst and concluded that China had already decided to take military action against India. There was serious contemplation in the White House that the crisis might lead to nuclear war, but the general conclusion was that a regional conventional war in South Asia pitting India and the Soviet Union against China, the US and Pakistan was more likely.

When the meeting took place, the Nixon White House learned that China's message had nothing to do with military moves in support of Pakistan. For his part, President Nixon realised that "Russia and China aren’t going to war."
In mid-December, Pakistani military forces surrendered in East Pakistan.
With US encouragement, Pakistan accepted an Indian cease-fire offer that would dramatically alter the Indian subcontinent, the release noted.
Tracing the history of the war, the volume released by the State Department described political crisis triggered by the electoral success of Bengali nationalists in East Pakistan, led by Sheik Mujibur Rahman and his Awami League and the announcement by Pakistan President Yahya Khan on March 1,1971, that the scheduled meetings of the newly elected National Assembly would be postponed indefinitely.

The announcement was met initially by popular demonstrations by the Awami League and the dispatch of additional troops to Dhaka by Pakistan's martial-law government. On March 15, Rahman announced that he was taking over the administration of East Pakistan and 10 days later the Army arrested him and moved to suppress what it viewed as a "secessionist" movement. The United States was loath to intervene in Pakistan's internal affairs, especially since Islamabad was Nixon’s secret conduit for a diplomatic opening to China.

The Pakistani Army's campaign against Bengali dissidents eventually led the US consulate in Dhaka to send a "dissent channel" message to Washington, which called for the United States to condemn the "indiscriminate killings." when Indian officials such as Foreign Minister Swaran Singh and Prime Minister Indira Gandhi came to Washington, the Nixon administration counselled non-intervention, but assumed that India planned to go to war. president Nixon had also warned Soviet officials not to encourage India and informed New Delhi that if it started a war with Pakistan, the United States would cut off aid. On November 22, when the war began, the Nixon administration cut off economic aid to India, and Nixon himself decided to "tilt" toward Pakistan. When Nixon learned that Indian war plans were designed to liberate "Bangladesh" and to destroy Pakistan's military armoured and air strength, he ordered the US carrier enterprise and its escorts into the Bay of Bengal.

History:
The United States supported Pakistan both politically and materially. Nixon, backed by Henry Kissinger, feared Soviet expansion into South and Southeast Asia. Pakistan was a close ally of the People's Republic of China, with whom Nixon had been negotiating a rapprochement and where he intended to visit in February 1972. Nixon feared that an Indian invasion of West Pakistan would mean total Soviet domination of the region, and that it would seriously undermine the global position of the United States and the regional position of America's new tacit ally, China. In order to demonstrate to China the bona fides of the United States as an ally, and in direct violation of the US Congress-imposed sanctions on Pakistan, Nixon sent military supplies to Pakistan, routing them through Jordan and Iran,while also encouraging China to increase its arms supplies to Pakistan.

The Nixon administration also ignored reports it received of the 'genocidal' activities of the Pakistani Army in East Pakistan, most notably the Blood telegram. When Pakistan's defeat in the eastern sector seemed certain, Nixon sent the USS Enterprise to the Bay of Bengal, a move deemed by the Indians as a nuclear threat. The Enterprise arrived on station on December 11, 1971. On 6 December and 13 December, the Soviet Navy dispatched two groups of ships, armed with nuclear missiles, from Vladivostok; they trailed U.S. Task Force 74 into the Indian Ocean from 18 December until 7 January 1972. The Soviets also sent a nuclear submarine to ward off the threat posed by USS Enterprise in the Indian Ocean. American policy towards the end of the war was dictated primarily by a need to restrict the escalation of war on the western sector to prevent the 'dismemberment' of West Pakistan .Years after the war, many American writers criticized the White House policies during the war as being badly flawed and ill-serving the interests of the United States.

The Soviet Union sympathized with the Bangladeshis, and supported the Indian Army and Mukti Bahini during the war, recognizing that the independence of Bangladesh would weaken the position of its rivals the United States and China. The USSR gave assurances to India that if a confrontation with the United States or China developed, it would take counter-measures. This assurance was enshrined in the Indo-Soviet friendship treaty signed in August 1971.