Obama asked to reach out to Narendra Modi

"If both sides can avoid stepping on each other's toes, especially in South Asia - an arena in which Modi will be fiercely protective of India's prerogatives - the United States could find itself in a potentially productive bilateral relationship with India," Tellis wrote.

"Precisely because such eventualities represent the most serious threat to US interests in South Asia today, the Obama administration ought to reach out publicly and generously to Modi as soon as it becomes clear that the Indian nation has chosen him as its next prime minister," he wrote.

"A congratulatory call from Obama to Modi followed by a visit to India by a US cabinet member or higher-ranking official would go a long way," he suggested.

"These overtures will not make up for the lost opportunity to engage Modi while he climbed the national stage or efface his accumulated grievances against Washington overnight," Tellis wrote.

"But they would be the necessary first step toward developing a relationship with a leader who will govern India for the next five years," he suggested.