It was George W. Bush’s “Nixon in China” moment. Speaking in Delhi in March 2006, Mr Bush hailed the “strategic partnership” between the US and India and the “historic” nuclear agreement at its heart. “It’s a necessary agreement,” he said. “It’s one that will help both our peoples.”

Today, however, the talk of history and necessity is long gone. US administration officials and congressional staffers admit that, barring an unforeseen breakthrough, there is now virtually no prospect that the US-India civil nuclear deal will receive final approval during Mr Bush’s time in office.