In May 1998, India stunned the world after it conducted nuclear tests in the Rajasthan desert.
The tests were reciprocated by its traditional rival, Pakistan, and dramatically raised the stakes in the stand-off over Kashmir, one of the world's longest-running feuds.
It was a move that was bitterly criticised internationally as well as within both countries.
India's Agni missiles have a 2,000km range
Many in India argued that by going nuclear it had lost its conventional military edge over Pakistan.
Others felt that the tests had opened the door to international - read American - intervention in Kashmir, something which India has traditionally opposed.
But five years later, the jury is still out on whether India lost more than it gained by going nuclear.
Increasingly, it is being felt that by becoming part of the nuclear club, India has forced the world to take it seriously and strengthened its diplomatic position, particularly over Kashmir.
Indian diplomats say that following the tests countries such as France, Germany and the United States began engaging Delhi, particularly in strategic and security dialogues.
Despite its concern, Washington quickly recognised that India was now a declared nuclear power and began to deal with Delhi on those terms.
"Although the United States did impose sanctions [following the tests] it also began to treat India more seriously," says C Rajamohan, strategic affairs editor of The Hindu newspaper.
It led to the beginning of a close relationship between the two countries, helped along by US interest in India's burgeoning economy and information technology boom.
Teresita Schaffer, South Asia analyst with the Washington-based Centre for Strategic and International Studies, says despite being apprehensive of India's nuclear status, the US decided to accept the reality very early on.
"It led to the first really strategic dialogue that India and the United States ever conducted," she says.
Observers also point out that the United States and other western nations were quite aware of the nuclear capabilities of India and Pakistan through the 80s and 90s.
India carried out its first test in 1974.
"The May tests ended India's nuclear ambiguity," says Mr Rajamohan.
But the South Asian nuclear tests also brought world attention to the continuing conflict between the two countries over Kashmir.
"It drew their attention to the threat of nuclear conflict in the subcontinent and led to them take active steps to prevent it," says retired Indian diplomat Muchkund Dubey.
India has long held the position that the dispute should be settled bilaterally between Delhi and Islamabad, with no place for a third party.
Kashmir still remains a worry
But many now believe that American intervention in Kashmir actually worked in India's favour.
During the Kargil conflict, when armed militants backed by the Pakistan army occupied strategic peaks in Indian-administered Kashmir, it was US pressure that forced Islamabad to back off, handing India a key diplomatic victory.
And after an attack on India's parliament in December 2001, which Delhi blamed on Pakistan-based Islamic militants, Washington pressed Pakistan's military ruler, General Pervez Musharraf, to take action against militant groups based on its territory.
Despite the heated rhetoric emerging out of Delhi, India's restraint on the ground in both situations earned it sympathy internationally - delivering diplomatic dividends.
Privately, senior officials in both countries suggest that the United States has begun to favour India's position on Kashmir, even seriously considering a possible division of the state or converting the ceasefire line into an international border.
A recent CIA map showed Kashmir divided into Indian and Pakistani territory, in what is seen as a tacit recognition of the situation on the ground.
Nevertheless, the international community - Washington included - is critically aware that Kashmir still remains one of the major unresolved conflicts in the world.
"The biggest potential worry is still an India-Pakistan war," says Teresita Schaffer.
Perhaps this is why India is less apprehensive of US intervention than before.
It is willing to allow Washington to engage in the conflict in some capacity, confident of the fact that Delhi's post-nuclear relationship with the US has secured its interests.