Rajiv Gandhi was assassinated 1991
Any military victory in the civil war in Sri Lanka will almost certainly see pressure for the re-emergence of India in contributing to a settlement.
Since the emergence of full-blooded Tamil militancy in Sri Lanka in the 1980s, the two neighbours have circled each other in an uncertain diplomatic tango, sometimes seeing eye to eye but more often holding each other at arm's length.
It was more more than 20 years ago that the then Indian Prime Minister, Rajiv Gandhi, first assumed the mantle of honest broker.
Between 1985-1986 he arranged face-to-face talks between Sinhalese politicians and the angry young men who had taken up weapons to fight for a Tamil homeland.
The failure of those talks, in the Himalayan kingdom of Bhutan, foundered on the two issues that in one form or another have scuppered all subsequent peace efforts.
Firstly, the refusal of successive governments in Colombo to cede sovereignty to people it regards as terrorists.
Tamil Tiger leader Prabhakaran has led the fight for independence
Secondly, the equally strong insistence of Tamil fighters to win what they regard as meaningful independence in the Tamil-majority areas of the north and east of the island, the putative "state" they call Eelam.
The eventual deployment of Indian troops inside Sri Lanka, as part of an accord reached between Delhi and Colombo, produced so much hostility among the majority Sinhalese population they had to be withdrawn.
But nor were the Tamil Tigers, under their leader Velupillai Prabhakaran, any more trusting. Both sides alleged human rights abuses against Indian forces, and both sides wanted them gone.
It still came as a shock in 1991 when Rajiv Gandhi was assassinated by a suspected Tamil suicide bomber.
Since then, whenever any other country has come forward to try to bring about reconciliation in Sri Lanka, there has been a reluctance from India to re-engage.
In 2002, when the Norwegian government sought to bring the two sides together, India sent diplomatic rather than political negotiators to the talks in Oslo.
For most of the past decade, with neither the Sri Lankan army nor the Tamil Tigers looking strong enough to triumph on the battlefield, it made sense for India to remain aloof.
But whenever the Tamil Tigers have been in serious trouble in the past they have always been adept at stirring up support among Tamils living abroad - especially more than 60 million of them living in the Indian state of Tamil Nadu.
In the view of many Indian Tamils, the narrow stretch of water separating Sri Lanka from India is less of an international border than an inconvenience between cousins and neighbours.
It is a uniquely strong connection, a bonding not only of language and culture but also the Hindu religion.
It is this sense of Tamil kinship that makes events in Sri Lanka a calculable factor in India's domestic politics.
Anything that is seen to imperil the Tamil cause in Sri Lanka has the potential to become a major headache for politicians in Delhi.
Yet any attempt to intervene is bound to stoke up all the deeply rooted mistrust and suspicion of a Sinhalese population that's lived for generations in the shadow of a powerful giant. Whatever the final military outcome in Sri Lanka, the political dilemma for India has hardly changed at all.