The prospect of a strongly nationalistic regime taking power in New Delhi has sparked concern in neighboring capitals that India could revert to playing the role of regional bully.
Surrounding states were just getting used to the consensual approach of the outgoing prime minister, Inder Kumar Gujral.
The first to feel the heat of a Bharatiya Janata Party-led government could be Pakistan, which has fought three wars with India since the two countries gained independence in 1947.
Although high-level talks resumed a year ago after a long hiatus, there has been little progress on core issues such as the disputed territory of Kashmir, which the BJP has threatened to seize.
"If the BJP does come to power we can expect India to become a much more insular state and that would harden the stand-off with Pakistan," says Agha Murtaza Pooya, former chairman of the Institute of Strategic Studies in Islamabad, Pakistan.
According to Mr Pooya, any move by the government to arm India with nuclear weapons would fuel an arms race on the subcontinent and invite the threat of US sanctions. "There is already a lot of pressure for Pakistan to shed its ambivalent stand on the nuclear issue and bring the bomb out of the basement. If the BJP comes to power we'll be pushing each other on the nuclear weapons issue," he adds.
Bangladesh, Nepal, and Sri Lanka will also be watching closely for any shifts in India's foreign policy. But according to Prof. Brahma Chellaney, a defense expert at the Center for Policy Research in New Delhi, India's smaller neighbors have little to fear from a BJP-led government.
"You must remember that it was ... Atal Behari Vajpayee who set in motion the idea that India should take a conciliatory approach to its neighbors when he became foreign minister in the Janata Government in 1978."