Washington is in the throes of an Indian summer. As the mercury rises, so does the buzz surrounding Manmohan Singh’s recent trip to Washington. Dr Singh returns home with an assurance of US friendship and President Bush’s personal commitment to expand civil nuclear cooperation with India at the expense of a strained international non-proliferation system.

A major driver in the administration’s radical overtures to New Delhi has been China. India’s burgeoning economy, democratic ideals, and second largest standing army in the world have caught the Bush administration’s eye as it looks to preserve US preeminence in Asia by balancing China with India. This ambition partly underpins the US’s decision to make India a ‘‘major world power.’’

Yet in the midst of its India euphoria, the Bush administration ought to curb its enthusiasm and consider an axiom from the Mahabharata: for a king ‘‘no one is his friend, no one is his enemy. Circumstances make enemies and friends.’’

While India has a pressing stake in curbing China’s rise with US assistance, there seems to be limited awareness in the US of shared Sino-Indian interests that may produce friction in the US-Indian relationship. Three areas come to mind: economics and energy; domestic politics; and geo-politics.

Like China, India is a developing country whose priority remains maintaining growth and alleviating poverty. An important ingredient in this mix is trade. After the EU, the US is currently India’s largest trade partner at $20 billion. But look who’s next in line at around $15 billion: China.

Stronger economic ties will create stronger constituents for peace in both countries and raise the threshold for conflict. This raises a key question. In what scenarios would India deem siding with the US against China worth jeopardising its commercial links with China?

India and China are also united in their quest for energy to fuel their growth. Their competition for equity stakes in exploration projects has been stiff. But both sides are also calling for exploring joint-bidding options and an Asian oil and gas grid to end what the Indian Oil Minister has dubbed ‘‘wretched Western dominance.’’

Much to the US’s dismay, their partners have included Iran where they share stakes in certain projects. Secretary Rice has made clear US opposition to a future Iran-Pakistan-India pipeline but India has remained defiant as per Dr Singh’s rejoinder: ‘‘This is an affair between Iran, us, and Pakistan. If the three countries agree, that should be the end of the matter...We are not a client state.’’ The Indian Oil Ministry has even called for extending the pipeline to China though the prospects seem remote. Meanwhile, the pipeline itself remains fraught with challenges related to security and cost-effectiveness.

Even as the US agrees to assist India in generating nuclear energy, it is unlikely to wean India from Iran or Iranian energy. Tehran is an invaluable friend to New Delhi in a tough neighborhood and energy security is a critical priority for India. Keeping its options open may put it at odds with the US even as it competes and cooperates with China.

A Sino-Indian convergence also exists in the WTO where both are championing the developing world’s cause of greater market access to the developed world including the US.

There is a historical context to this, including China and India’s colonial legacies and their involvement in the Afro-Asian summits. The Cold War may be over, but developing and developed countries remain. While India and China will jockey for leading the former bloc, the US should be prepared to hear them speak with one firm voice.

India may also break ranks with the US on China due to domestic politics. In the Congress-led coalition government, the Left parties are a key ally and are increasingly asserting their views in foreign policy. The main Communist party has called for putting the June 2005 US-Indian defense framework agreement ‘‘in a dustbin’’ because it compromises India’s sovereignty.

Yet the Left is more amenable to closer ties with China. Should it continue to come to power in New Delhi as part of India’s revolving coalition governments, it may throw up roadblocks to a US-Indian strategic relationship that is even obliquely anti-China. The United States will have to live with the different shades of opinion in India’s colorful democracy on India’s US and China policy.

A final trigger for Sino-Indian convergence is the US’s sole superpower status and its propensity for unilateralism. India like China has watched this trend with great concern and continues to withhold any meaningful support to US efforts in Iraq.

One expression of this discontent is a fictitious account published by a former Indian Army Chief titled The Writing on the Wall: India Checkmates America in 2017. The book describes how the US’s disregard of the UN leading up to the war in Iraq puts India on notice that it could face military action . India responds by modernising its military and concluding an agreement with Russia, Vietnam, and China. Following a short war that pits India against Pakistan and the US, India withstands a US missile attack and knocks out telephonic communications across the US with an electromagnetic pulse, ending hostilities.

From fiction to reality, in their first stand-alone trilateral meeting last month, the Foreign Ministers of India, China, and Russia called for a ‘‘democratisation of international relations, a consistent application of the principles of multilaterality in problem settlement, and the strengthening of the role of the United Nations.’’

In short, as India leverages US strength for its own ends, India’s Nehruvian strain of non-alignment and multilateralism may not always be able to digest the US’s preponderance of power. Here too, India may be compelled to close ranks with China and others.

Few in the US would argue against the merits of a stronger US-Indian relationship. Areas of cooperation include promoting democracy; protecting Indian Ocean sea-lanes; combating terrorism and the proliferation of weapons of mass destruction; and engaging in trade and hi-tech commerce.

But an abundance of common interests does not codify loyalties. In today’s era of open boundaries and economies, states have diffuse interests and threats and require fluid foreign relations. India has a range of national interests that the US will not always be able to fulfill and vice versa. Greater sensitivity in both capitals to a dissonance of national interests is ironically critical to an honest and durable relationship.

But will the Bush administration tolerate ‘‘deviance’’ from a strategic partner as it injects political capital, money and machinery into the relationship? Time will tell. Meanwhile, as a new and promising chapter begins in US-Indian relations, US policy makers and analysts would be prudent to ponder Sino-Indian convergences along with applauding US-Indian ones.