The Reagan administration has made a significant gesture to Rajiv Gandhi in the prelude to his visit this week by taking cautious exploratory steps to liberalize exports of American high technology to India. But high tech alone will not bring geopolitical payoffs for America in New Delhi unless this country rules out new commitments of India-focused military equipment to Pakistan, following fulfillment of its existing $1.5 billion arms aid agreement next year.

Rajiv Gandhi's emergence offers an unprecedented opportunity to reverse the present dangerous drift in Indo-American relations because it coincides with India's economic emergence into the high-tech age.

The potential for Indo-U.S. economic cooperation is expanding as India's burgeoning industries seek computers and electronic technology from the United States, Western Europe and Japan -- technology the Soviet bloc does not possess.

Given a favorable political climate, growing economic interdependencies would help to draw India away from its present Soviet-tilted brand of nonalignment. But barring a shift in military aid policy, the political and psychological distance between India and the United States is likely to grow. New Delhi will increasingly perceive a geopolitical community of interest with the Soviet Union and will view the United States, in turn, as the principal barrier to its ambitions for regional preeminence. In such a climate, while New Delhi will no doubt take as much American high technology as it can get, the United States will not receive significant political benefits from a relaxation of high-tech export controls.

India's nonaligned foreign policy is not designed to achieve equidistance between the superpowers but rather to make use of the superpowers o promote Indian interests, even if this means temporarily leaning in one direction or the other. For more than three decades, the Soviet Union has identified itself with Indian regional aspirations, while the United States has generally sided with Pakistan and China. India has adapted to this situation by frequently tilting toward the Soviet Union. Conversely, if the United States were to give greater recognition to Indian regional primacy, India would gradually modify its posture in the decades ahead.

So far, New Delhi has carefully stopped short of de facto military collaboration with Moscow, but it would be unwise to assume such restraint will continue to govern Indian policy regardless of the nature of U.S. policies toward Pakistan. An atmosphere of xenophobic resentment is building up among many key Indian military and political figures. In time, as Indian naval power continues to grow, U.S. military access to the Indian Ocean will be increasingly affected by the climate of U.S. relations with New Delhi.

To some extent it was possible for Indians to forgive and forget after the first $1 billion U.S. military aid agreement with Pakistan in the 1950s. The United States was, after all, a newcomer on the Asian scene and had shown good will toward India through its economic help. President Eisenhower had given a formal undertaking that U.S. weapons were intended solely for use against communist aggressors, pledging the United States would not permit their use against India.

This time administration officials are not seeking to justify American arms aid to Pakistan solely in terms of the threat posed by Soviet forces in Afghanistan. On the contrary, they acknowledge that Islamabad wants American help primarily to strengthen itself vis-a-vis New Delhi, and they have pointedly declined to give either public or private promises that the United States would seek to prevent its weaponry from being used against India.

Recalling the dispatch of the USS Enterprise to the Bay of Bengal during the 1971 Bangladesh war, many Indians fear intervention in any new Indo-Pakistani conflict by the U.S. carrier battle group now stationed permanently in the northern Arabian Sea. At the very least, they fear, the United States could share intelligence with Islamabad without New Delhi's even knowing.

Conceivably, some form of U.S. military involvement in South Asia could become necessary in the context of growing tensions on the Afghanistan-Pakistan border. But President Reagan should reassure India that the mission of the carrier battle group relates to the protection of U.S. interests in Afghanistan and the Gulf and that it would not be used to support Pakistan in any South Asian conflict limited to India and Pakistan. The president should also serve notice that the United States will not provide Pakistan with weaponry primarily suited for use on the Indian border, including more F16s and heavy tanks and E2 "mini-AWACS." Gandhi, for his part, should be prepared to live with selective U.S. help for Pakistan on the Afghan frontier in ways that do not threaten India, such as light tanks and howitzers, mobile radar and certain types of air defense systems.

The United States should seek to avoid entanglement in the military aspects of this rivalry, especially in the context of the growing nuclear competition between New Delhi and Islamabad.

Such a detached posture would be difficult to maintain if an escalating conflict in Afghanistan led to stepped-up Soviet military pressures on Pakistan. Thus, both the United States and India should give unambiguous support to the United Nations mediation efforts on Afghanistan resuming June 20 in Geneva, so that Soviet readiness for a combat force withdrawal can be put to the test. So far, the United States has refused to accept a Soviet force withdrawal that would leave the present Kabul regime in place, at least initially, as envisaged in the U.N. formula. India has often acted as if a withdrawal of foreign support for the Afghan resistance would automatically ensure a Soviet withdrawal. New Delhi has not pushed Moscow to accept the U.N. formula, which would require a force withdrawal within a defined time period, orchestrated with the cessation of other foreign involvement.

What is needed is serious and urgent support for the U.N. effort by both the United States and India, together with a redefinition of U.S. military aid to Pakistan. In the absence of greater harmonization of policies throughout the South Asian region, the prospects for any basic improvement in Indo-American relations appear bleak.