WASHINGTON — After decades of mistrust and fitful reconciliation efforts, the relationship between India and the United States is expected to reach new heights of cooperation on Tuesday during a visit by the Indian prime minister, and Donald J. Trump can claim at least some of the credit.
The prime minister, Narendra Modi, who is making his second visit to the White House in two years, is expected to approve a range of agreements with the United States on security cooperation and economic ties. He is also expected to announce a crucial step toward ratification of the Paris agreement to limit greenhouse gases.
But a formal alliance with the United States is not in the offing; India has no alliances. Still, Mr. Modi appears willing to set aside decades of standoffishness — with postcolonial roots — to cement increasingly close ties, perhaps because the next American leader may not share President Obama’s enthusiasm for India.
The news media in India has extensively chronicled comments by Mr. Trump that critics have called racist, his “America First” views and his unorthodox campaign. While Mr. Trump, the presumptive Republican presidential nominee, has said little about India, his vows to tighten immigration policies worry Indian officials.
“Modi wants to get as much as he can out of Obama’s last months in office,” said Ashley J. Tellis, a senior associate at the Carnegie Endowment for International Peace.
Mr. Modi will meet with Mr. Obama at the White House on Tuesday morning, and the two are expected to have a working lunch. The last time Mr. Modi visited, in September 2014, he was invited to dinner but announced that he was observing a religious fast. So Mr. Obama had the awkward task of eating before a guest who sipped only water. On Tuesday, Mr. Modi is expected to eat.
On Wednesday, he will address both houses of Congress, becoming the fifth Indian prime minister to deliver such a speech.
The most important moment in Mr. Modi’s visit is likely to come Tuesday morning, when he is expected to announce that India will formally comply with the Paris climate change agreement. So far, countries representing about 50 percent of global emissions have announced that they will submit legal paperwork to the United Nations documenting their compliance with the deal.
The pact will become binding once countries representing 55 percent of global emissions comply. The inclusion of India, the world’s third-largest emitter, after China and the United States, would guarantee that the deal will go into effect before the next American president takes office.
Mr. Trump has vowed to “cancel” the Paris climate agreement if elected, something Mr. Obama is eager to prevent. Once the accord enters into legal force, no nation can legally withdraw for four years.
“If the Paris agreement achieves ratification before Inauguration Day, it would be impossible for the Trump administration to renegotiate or even drop out during the first presidential term,” said Robert N. Stavins, the director of the environmental economics program at Harvard.
Mr. Obama and Mr. Modi may also announce a separate agreement to cut the use of hydrofluorocarbons, potent planet-warming chemicals produced by coolants in refrigerators and air-conditioners. India is among the last holdouts to an agreement phasing out the chemicals.
In addition, Indian diplomats are hoping for a deal in which the United States would provide financing or other incentives to help support the expansion of affordable wind- and solar-powered electricity in India.
The two countries are expected to announce a military-logistics deal that would allow their forces to help each other with crucial supplies, and the United States is expected to agree to allow India to receive military technology usually reserved only for its closest allies.
India’s increasing willingness to form military partnerships with the United States is in part a result of its deepening worries about China. Recent patrols by Chinese submarines in the Bay of Bengal have unnerved New Delhi, and a 2014 visit to India by the Chinese president, Xi Jinping, did nothing to soothe Indian sensibilities, as Chinese troops made an incursion into border territory that India claims as its own. China’s refusal in the months since to resolve the territorial claims at the heart of the standoff has quietly infuriated Indian officials.
India is believed to be worried that China will become just as assertive in the Indian Ocean as it has been in the South China Sea, where Beijing has claimed vast reaches of ocean that neighboring countries have long seen as their own.
Another reason Washington and New Delhi have grown so close is the increasingly testy relationship between the United States and Pakistan, India’s longtime rival. Although Pakistan is formally an ally of the United States, American officials have made clear that India has displaced Pakistan in American interests and hearts.
“We have much more to do with India today than has to do with Pakistan,” Defense Secretary Ashton B. Carter said in April. “There is important business with respect to Pakistan, but we have much more, a whole global agenda with India, agenda that covers all kinds of issues.”
Economic cooperation is also on the agenda for Tuesday’s meeting, and Mr. Modi is expected to meet with business leaders during his stay. India has the world’s fastest-growing large economy, but it is not growing fast enough to provide jobs to even a significant fraction of the one million people entering the work force there every month. Mr. Modi has largely failed to deliver the kind of major economic overhauls he was expected to carry out after his election two years ago.
India’s economy is dominated by a few elite families who insist on limits to foreign companies and investments to protect their privileged status. Those families largely fund India’s political parties through vast unreported cash contributions, making any changes to the country’s endemic and enervating protectionism difficult to undertake.