"In my personal opinion, this is a seminal moment and potentially a game changing opportunity for the relationship.
This is a relationship in which the President has invested a great deal of time, trying to elevate the nature of our partnership," said Reiner, who is the point person for India and South Asia in the National Security Council.
Responding to questions, the senior White House official said during the three-day visit progress could be seen in key areas of defence and security, clean energy and climate change and nuclear co-operation.
These are all pieces of strategic co-operation that the US not only has an interest in continuing forward, but had really heightened level of ability to engage since September, he added.
"After the President accepted Prime Minister Narendra Modi's invitation to be the chief guest at the Republic Day, the message from the top was to seize the opportunity in not just a symbolic way but also in terms of substance", he said.
"The very clear message internally here was accepting that symbolic gesture, accepting this huge opportunity was also to use this moment to make it substantive. The message from the very beginning was let's seize this opportunity not only in a symbolic way but also in terms of substantive way," he said.
After the September 30 Obama-Modi meeting there has been reinvigoration of the two bureaucracies, driving things at a very senior level in order to clear out the underbrush and move forward with those elements of strategic partnership.
"Going forward, we have a very robust agenda," Reiner said, adding everything they are working on is very much facilitated by the fact that there is a very nice relationship between the two leaders.
"This visit only offers to increase that opportunity, he said, adding that these could be in areas like space cooperation, cancer research or intellectual property. So there is an increase in momentum to the relationship by the leadership-level engagement", he said.
(PTI)