America's former Ambassador to India says China is watching President Obama's visit to Delhi "through a microscope".

Tim Roemer believes that with a bit more foreign policy confidence, India can play a useful role in balancing power in Asia. Translated, that means America is keen to have a counter to China's clout and is wooing India to play that role.

This trip is clearly a big deal for Indian Prime Minister Narendra Modi. As head of the world's largest democracy, he wants to assume the role of global statesman - and sitting next to a smiling Mr Obama at the Republic Day parade is a great PR coup for him.

But it's worth remembering that questions over Mr Modi's human rights record and Hindu nationalist policies meant that a year ago the Indian leader couldn't even have obtained a visa to come to America.

So for Mr Obama, there are risks in this relationship too.