New Delhi ( CNN ) India and the United States , the two largest democracies , seem like natural allies . The kinship between their leaders , however , has been a bit of a surprise . There are , of course , the obvious perceptual differences : President Barack Obama studied law at Harvard , relishes golf and prefers his suits sober , in dark gray or navy blue . Prime Minister Narendra Modi had a modest education , swears by yoga and readily wears flamboyant hats depicting India 's diverse heritage . And then there 's the small matter of paperwork : Modi was a pariah in the United States just one year ago , his visa revoked over his handling of riots in 2002 , when he was chief minister of the state of Gujarat . But what a difference a year — and a big electoral victory — makes . When President Obama arrives in New Delhi on Sunday , he will have met Modi four times in five months : at the White House , at the East Asia Summit in Myanmar , at the G20 Summit in Australia and now in India . The latest visit is the most significant : Obama will become the first U.S. president to visit India twice , and the first American chief guest at India 's Republic Day parade . It 's an open declaration of friendship . What explains this unlikely rapport ? Aides on both sides have pointed out that when the two leaders met in Washington in September , there was a palpable chemistry . They shared a sense of priorities , of where they wanted the alliance to head . On his previous visit to India , in 2009 , Obama spoke of the two democracies forming one of the `` defining partnerships '' of the 21st century . But in those initial years , the partnership became strained . First came a stalled nuclear deal ; later , a needless spat over an Indian diplomat in New York . India 's disappointing growth , meanwhile , seemed to lead to declining interest . Modi has now successfully hit the reset button . By not bearing a grudge against Washington for blacklisting him , and by wooing American business with gusto , he has revived a flagging partnership . Americans who have negotiated with Indian teams under Modi say it 's evident the new Prime Minister has been clear with his envoys : It 's time to fix things with Washington . And so it comes down to Modi and Obama in New Delhi . Indian TV channels alternate between flashing banners saying `` Namaste Obama '' one minute and asking about `` deliverables '' from the summit the next . For days , teams in London have been hammering out a potential deal to trade civilian nuclear energy . There is talk of increased ties on defense , and on renewable energy . Climate change will be an important topic for both sides : India generates more than half its energy needs from the dirtiest fuel in common use , coal . And there will be much more soaring rhetoric . On a visit earlier this month , U.S. Secretary of State John Kerry called for trade between the two countries to multiply five times . That will be unattainable for quite a while . It may be asking too much to judge the Modi-Obama summit through deliverables alone . After all , the invitation came just a couple of months ago when the two met in Myanmar . Symbolism has inherent value : By visiting India for a second time , Obama is putting New Delhi on the map in Washington . In India , he will be seen by a generation of young Indians on TV ; they will glow with pride that the world 's most powerful man has come to town once again . The real work between the two countries will continue at a smaller , ongoing level : with increased people-to-people contact , with more trade , with more tourism , with an energized Indian diaspora in the United States , and with many , many more days of talks between the two countries ' envoys . In many ways , the people on both sides are ahead of policy . According to a Pew Research Center survey last year , 58 % of Indians view Americans favorably , with only 18 % holding an unfavorable view . It 's time for government to catch up . With both India and the United States benefiting from lower crude prices and a growth upswing , this is as good a time as any .
U.S. President Barack Obama travels to India this weekend . Ravi Agrawal : The White House is expected to announce a new trade deal with India, which would be the largest bilateral agreement between two countries in history.