Against a backdrop of saris, elephant-shaped flower ar­rangements and bowls of lotus-blossom ice cream, President George W. Bush raised his water glass to Manmohan Singh, India’s prime minister. “India and the United States are separated by half the globe. Yet today our two nations are closer than ever before.”

His toast, made last July in the State Dining Room at the White House, marked a moment of recognition by the US of India’s status as one of the world’s emerging great powers. For some diplomats involved, that day has already taken on the sepia hues of history, evoking comparisons with the strategic embrace of China by President Richard Nixon in 1972.