India and Pakistan are taking a major step toward easing their bitter, often intractable rivalry. Today, Indian Prime Minister Rajiv Gandhi begins his first official visit to Pakistan for a summit of South Asian nations. In a celebrity meeting between the youthful heirs of the region's most prominent political families, Mr. Gandhi will hold a series of talks with Pakistan's new prime minister, Benazir Bhutto.
The death in August of strong man Mohammed Zia ul-Haq and Prime Minister Bhutto's election have raised high hopes of a subcontinental thaw that only six months ago seemed unthinkable.
``We're at an historic crossroads in our relations,'' says a Pakistani diplomat here. ``If we miss this opportunity, it will be gone.''
The leaders' talks will be interspersed, over three days, with annual-meeting sessions of the seven-nation South Asian Association for Regional Cooperation. Capping these events will be the signing of an agreement not to attack each other's nuclear plants, Indian and Pakistani officials say.
The prospect of warmer ties has heightened excitement on both sides of the border. In recent months, the Indian public has been fascinated by Bhutto's stunning rise to power, and New Delhi has quieted its constant challenges to Islamabad.
In Pakistan, the return of a democratic government, the first in more than a decade, has given the country a new confidence in dealing with its giant neighbor, Pakistanis say.
Still, a deep distrust underlies contacts. In both nations there are bitter memories of the 1947 partition of British India which split or uprooted millions of families on both sides.
More recently, the threat of a nuclear arms race has shadowed South Asia. India, which exploded a nuclear device in 1974, insists it has no bomb. Several analysts say, however, that India has the capability to build one and is rapidly developing a delivery system.
Pakistan says it opposes nuclear weapons - despite evidence that it is close to developing nuclear weapons capability, at least partly with stolen Western technology. India has criticized the United States, a key Pakistani ally, for not pressuring Islamabad to block the program.
Three years ago, amid growing fears that India might launch a preemptive strike against Pakistan's Kahuta nuclear plant, Gandhi and Zia pledged not to attack nuclear installations. The pledge came as Gandhi was trying to improve relations with neighbors, an effort that dissolved as his political fortunes sagged at home. India also accused Pakistan of fueling the ethnic Sikh insurgency in border areas.
In early 1987, tensions threatened to spark the fourth war between the two countries. 3 Pakistani officials hope the nuclear pact, which will be accompanied by measures to boost economic and cultural ties, will pressure India to agree to make the region a nuclear-free zone.
But Western analysts in New Delhi say that India - with its sights set on becoming a major international player - will not limit its nuclear options.
``This is a good first step,'' says a senior diplomat. ``But after this, progress on the nuclear issue will be very slow.''
Better ties could be sabotaged by fundamentalist forces in Muslim Pakistan and in India, which was founded as a secular state but is predominantly Hindu.
Western and Indian analysts say New Delhi will move - but slowly - toward a new policy. Indian officials want to be cautious not to stir anti-India feeling in Pakistan. And Gandhi, who faces general elections next year, will have to avoid antagonizing the anti-Pakistan lobby.
``Given the high public expectations for this visit, the hard-liners have been forced to sit back,'' says an Indian official. ``But the prime minister will have to move cautiously and carry the anti-Pakistan elements along with him.''
Indian overtures to Pakistan, and to another erstwhile enemy, China - which Gandhi visited last week - appear part of major political shifts in Asia spearheaded by actions of Soviet leader Mikhail Gorbachev. These include the Soviet troop pullout from Afghanistan and Mr. Gorbachev's initiative to patch up animosities with China. The Soviet Union is a key ally and weapons supplier of India.
``The question is how to manage the turbulence between the two countries,'' says analyst Jasjit Singh. ``The window of opportunity has opened. But to say that the doors are opening is, at this point, too much.''