Back on June 27, the White House abruptly postponed a summit, scheduled to take place in Washington on July 6, between Secretary of State Mike Pompeo and Secretary of Defense James Mattis and their Indian counterparts Sushma Swaraj and Nirmala Sitharaman. Pompeo, in a phone call with Swaraj, cited “unavoidable reasons” for delaying what would have been the first installment of the 2+2 dialogue.

With this decision, which came on the heels of growing economic tensions, the US-India relationship has taken one of its biggest tumbles in years. For a partnership that’s enjoyed ample momentum and rapid growth since the early 1990s, this abrupt shift is jarring. But it’s not surprising.

Indeed, if there’s one sure thing about US foreign policy in the Donald Trump era, it’s that no US partnership — no matter how deep or “natural” — is foolproof. Washington’s statecraft has become utterly unpredictable. America now bullies its best friends (think Great Britain and Australia) and butters up its bitter enemies (hello North Korea).

At first, the US-India relationship appeared to be the exception — a rare island of calm in the stormy waters of Trump’s international diplomacy. Indeed, after taking office, the Trump administration initially upheld a long-standing bipartisan consensus in both capitals in favor of a deep bilateral partnership. Each side has emphasized shared values of democracy and a convergence of strategic concerns, particularly terrorism in South Asia and the expanding footprint of China across the Asia-Pacific region.

Early on, Trump administration officials extolled the relationship’s importance. In April 2017, in the first visit to India by a senior Trump White House official, national security adviser H.R. McMaster affirmed India’s status as a major defense partner — a designation first conferred by the Obama administration. One year ago, Trump and Indian Prime Minister Narendra Modi had a warm and productive summit in Washington. More recently, in February, US Counterterrorism Coordinator Nathan Sales effusively described India as an “incredibly important, incredibly valuable, and incredibly close counterterrorism partner of the United States.”

Early signs of tensions had emerged during the first few months of 2017, when Trump upset New Delhi for offering no public response to three violent attacks on Indian Americans, two of them deadly, and for announcing plans to rein in the H-1B visa program.

Michael Kugelman

And then the tables turned in a big way. Early signs of tensions had emerged during the first few months of 2017, when Trump upset New Delhi for offering no public response to three violent attacks on Indian Americans, two of them deadly, and for announcing plans to rein in the H-1B visa program, which enables high-skilled foreigners to live in America. An estimated 70 percent of these visas are awarded to Indians. Trump also rankled India in June 2017, when, while announcing his decision to pull out of the Paris climate treaty, he falsely accused India of signing the agreement only after receiving billions of dollars in foreign aid from developed countries.

In more recent weeks, economic relations have suffered several body blows. This isn’t unprecedented; pre-Trump, US-India relations often got bogged down in trade disputes and concerns about India’s investment environment. Economic ties have long been the Achilles’ heel of the partnership, while a rapidly growing defense partnership has been its glue.

This time, however, it is more serious. India has become ensnared in the widening net of Trump’s expanding trade war. The president’s decision to impose new tariffs on steel and aluminum products prompted India, whom he has accused of slapping 100 percent tariffs on US goods, to reciprocate by imposing new levies on nearly 30 US products. Trump’s position has been uncompromising; he rejected as insufficient India’s decision in February to lower tariffs on Harley-Davidson motorcycles from 75 to 50 percent. This blow to free trade is no small matter for New Delhi; America is India’s largest trading partner. The steel and aluminum tariffs risk undercutting “Make in India,” a flagship Modi government effort meant to strengthen a sluggish Indian manufacturing sector.

Meanwhile, few nations are more affected by the administration’s new sanctions on Iran and Russia than India. These sanctions ban nations from doing business with Tehran and Moscow — critical Indian energy and arms suppliers, respectively. New Delhi has signaled its intention to go ahead and conclude a major air defense missile system deal with Moscow. Meanwhile, India surely wasn’t pleased about a White House request on June 27 that it end all oil imports from Iran by November 4. In the previous fiscal year, Iran was India’s third-largest oil supplier.

These tension points reflect just how dramatically a domestic US program — that of “America First” — can impact foreign policy. Visa reforms, new tariffs, sanctions regimes; these are all intended, in the eyes of the Trump administration, to protect American jobs and to keep Americans safe. And yet these inward-focused measures are now colliding with some of America’s most critical external partnerships.

This is not to say the US-India relationship is poised for a rupture. It enjoys sufficiently deep repositories of goodwill to weather the current storm. At the very moment when the 2+2 dialogue was postponed, US Ambassador to the UN Nikki Haley was on a visit to India singing the relationship’s praises. Still, the postponement suggests that economic tensions, ominously, could spill into the traditionally safe space of defense.

For its part, the Trump administration insists bilateral concerns were not why the 2+2 dialogue was delayed. The real reason was a scheduling conflict: Pompeo had to adjust his calendar to visit North Korea to discuss denuclearization plans. Alas, that trip didn’t go well; Pyongyang described the talks as “regrettable” and criticized Washington for making unreasonable demands about denuclearization.

This all makes for bad optics. If Washington really considers New Delhi to be such an important strategic partner, why would it stand India up for North Korea of all countries? Couldn’t it at least have sent someone other than Pompeo to Pyongyang?

Regardless of the reason for postponing its high-level summit with India, Washington squandered an opportunity to reset a relationship in need of a reboot. Not long ago, the idea of a reset being needed would have seemed fanciful. Not any longer.

•  Michael Kugelman is deputy director of the Asia Program and senior associate for South Asia at the Woodrow Wilson International Center for Scholars. Twitter: @michaelkugelman