David A. Andelman, visiting scholar at the Center on National Security at Fordham Law School and director of its Red Lines Project, is a contributor to CNN and a columnist for USA Today. Author of "A Shattered Peace: Versailles 1919 and the Price We Pay Today," he was a foreign correspondent for The New York Times and CBS News in Asia and Europe. Follow him on Twitter @DavidAndelman. The views expressed in this commentary are his.

(CNN) Quietly, all but unheralded, Donald Trump has begun tilting significantly away from Pakistan and toward another South Asian ally -- a counterweight to China that could help tip the balance, particularly in the region's potentially most sensitive flashpoint, the South China Sea. That enemy of my enemy is India, and it is not an inconsiderable friend to have. At the same time, though, Trump's actions have opened another door to a resurgent China that could prove even more dangerous down the road.

So, when did this relationship with India develop? The United States and India have been allies for a while, but Trump and Indian Prime Minister Narendra Modi have significantly strengthened their bonds over the few months. Modi visited Trump in Washington last June, kicking off a new set of talks between the nations. And then at November's ASEAN Regional Forum in Manila, Philippines, the two leaders resolved to strengthen the US-India defense partnership, discussed expanding Indian oil imports from the United States to help shrink the trade gap and agreed to expand a supply line to Afghanistan that India was developing.

All this plays to India's advantage. India is hoping to find a big-power ally that can help it become a viable force against China, while at the same time maintaining security of its sea routes to the east. After all, more than two-thirds of India's entire trade volume arrives and departs by sea.

India's new " Look East Policy " involves not only bulking up its blue water naval capability but also launching a new intercontinental ballistic missile that puts all of China within range of attack. China is not taking this news well. China has been concerned for a while with India's surging economic growth, military reach and population expansion. This new policy only irritates China more.

To complicate matters, India's growth is surging at the very moment that China's is beginning to plateau. Last month, the International Monetary Fund revised Asia's economic growth upward largely on the strength of India's performance -- projecting an expansion in India of 7.5% this year and 7.8% next year, an increase over the 6.7% growth registered in 2017. By contrast, China is heading in the other direction -- its growth dropping from 6.8% last year to 6.6% this year and 6.4% next year.

And there is no suggestion that the United States is prepared to squeeze India's foreign trade as it has already shown an inclination to take on leading Chinese exports, raising tariffs substantially on solar panels and washing machines. Of course, American two-way trade with India is a fraction of the trade with China, but it has been rising rapidly and the Indian government has been receptive to the Trump administration's pressure to reduce the size of its trade deficit.

Most smaller Southeast Asian nations are also eager to see a newly resurgent India as a trade partner, but especially as a reliable balance to China, which has loomed over the region militarily as well as economically.

In this respect, India is very much flexing its muscles. Last month, India successfully test fired an intercontinental ballistic missile with a range of 3,400 to 3,600 miles. It's also looking to double its fleet of 12 state-of-the-art American made P-81 anti-submarine patrol aircraft, able to detect submarine activity from the air. This comes just as China has offered India's neighbors -- Bangladesh, Thailand and especially Pakistan -- advanced Yuan class submarines at a fraction of the price of European or American models.

In its nuclear arsenal, India already is believed to have 120 to 130 nuclear warheads , compared with China's 270, according to the Federation of American Scientists. Building a deliverable nuclear capacity has been a vital concern to India, until recently as a deterrent to the nation it has long seen as its mortal enemy: Pakistan, with 130 to 140 nuclear weapons. Which makes the current strategic situation in the region especially fraught, because both nations are believed to be bulking up their arsenals still further.

This confrontation comes at the very moment the Trump administration has entered into a bitter war of words with Pakistan, once a loyal South Asian nation. As he has done in other parts of the world, notably the Middle East, where the President has thrown America's support firmly to Saudi Arabia, last month Trump announced that he was withholding some $2 billion of security aid from Pakistan as punishment for the regime allegedly harboring terrorists who are actively working to further destabilize Afghanistan.

Not surprisingly, the Pakistani government has begun actively seeking new strategic partners. And, according to Chinese state-owned media, China has eagerly stepped in to assist. Already, China has investments and loans in Pakistan surpassing $100 billion . China has also, as CNN reported , made a major move into India's offshore neighbor, Sri Lanka, with a 99-year lease on a major port facility and some $15 billion in investments.

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All this has led a number of Asian nations, already skeptical of Trump after his withdrawal from the Trans Pacific Partnership, wondering how committed the United States is to providing a counterweight to Chinese hegemony across the region. While India could eventually prove to be such a counterweight, China has a significant head start.

Somehow, the United States has to find a way of choosing its friends more judiciously. It must also appreciate the consequences of choosing sides in a complex diplomatic and military game. At this point, though, the administration seems to have little understanding of the rules of the game, let alone the stakes involved.