File photo of US president Barack Obama.
President Barack Obama faces the prospect this week of having to offer his congratulations to Narendra Modi
, who was barred from the United States less than 10 years ago after the 2002 communal riots in Gujarat.
As voting concluded in the general election on Monday, four major exit polls showed Mr Modi set to become prime minister, with his BJP and its allies headed for a parliamentary majority. (Exit Polls: Numbers Stack Up in Favour of BJP-Led NDA
Mr Modi was shunned by Western nations for years after the riots killed more than 1,000 people in Gujarat, where he has been chief minister since 2001. He was denied a US visa in 2005 under the terms of a 1998 US law which bars entry to foreigners who have committed "particularly severe violations of religious freedom."
Mr Modi has denied any wrongdoing in 2002 and, in 2010, the Supreme Court ruled that he had no case to answer. (Narendra Modi-led BJP Set For Victory, Exit Polls Show
His rise on the national stage and the importance of relations with India, which the United States sees as a key counterbalance to China in Asia, has forced a rethink. Ambassadors of the European Union and the United States have met him to patch up relations. (Voters in India Expected to Give Narendra Modi a Mandate
The US State Department has repeatedly declined to spell out whether it will issue a visa to Mr Modi as Prime Minister, but analysts say it is all but certain he will be given one because of the "strategic" nature of the US-India relationship, which Mr Obama has called "one of the defining partnerships of the 21st century." (Barack Obama Looking Forward to Work With New Indian Government
On Monday the State Department described the Indian elections, which were spread over five weeks, as "an inspiring example of the power of the democratic process in action."
"We look forward to working with the leaders chosen by the Indian people to advance this important partnership and to set an ambitious agenda," spokeswoman Jen Psaki said.
In March, a report to the US Congress by a specialist in immigration policy, Ruth Wasem, noted the 2010 Supreme Court ruling and said that if Mr Modi were to become prime minister, he would be covered by diplomatic immunity and qualify for a visa.
One Congressional aide said if elected, Mr Modi could visit as early as September for the UN General Assembly in New York.
Ashley Tellis, a South Asia expert at the Carnegie Endowment for International Peace, said that if Mr Modi were elected, Secretary of State John Kerry should visit India as soon as possible and Mr Modi should be invited to the United States.
"I think the Obama administration will reach out to him if he is elected as prime minister as it would the leader of any other friendly state," Ms Tellis said.
Human rights groups Amnesty International and Human Rights Watch have not taken a position on the Modi visa issue, but said it was important for Washington to press India's new government to end impunity and promote freedom of expression.