Chandigarh: The recent decision of the US to impose 25% tariffs on Indian exports, coupled with threats of an undefined ‘penalty’ if New Delhi continued importing Russian oil and materiel, has cast an ominous shadow over the otherwise expanding US – India defence and strategic partnership.And while defence ties had previously remained insulated from trade disputes, security officials in Delhi feared that the scope and scale of current negotiations over assorted defence equipment purchases and joint military ventures, could lead to ‘crippling delays’ in bureaucratic approvals, and possibly even project cancellations.These officials believed that enduring economic tensions over tariffs could reinforce Washington’s chronic unwillingness to transfer sensitive defence technologies to India, thereby undermining the strategic momentum that bilateral military-industrial collaboration had gathered in recent decades that included materiel commerce worth over $22 billion to the US.Pending bilateral defence projectsIndia’s earlier reluctance to fully embrace US defence cooperation-rooted in strategic autonomy concerns, too, was resurfacing amid the tariff row.“This (tariff debate) has rekindled doubts in Delhi about Washington’s reliability as a long-term partner, slowing momentum on key deals and raising fears of political conditionalities returning to bilateral military engagements,” said a former Ministry of Defence (MoD) official, on condition of anonymity.This unease, the former official added, only compounded memories of past sanctions and technology denials, prompting the military to begin ‘reassessing’ the depth and pace of its collaboration with Washington.Pending bilateral defence projects include big-ticket deals like the co-production of General Electric GE F414 engines by Hindustan Aeronautics Limited (HAL), agreed to in a memorandum of understanding in mid-2023, but awaiting finalisation due to differences over pricing and technology transfer.The GE-F414 is critical to powering the Indian Air Force’s (IAF) planned Tejas Mk2 Light Combat Aircraft advanced variant, the Indian Navy’s (INs) under-development Twin Engine Deck-Based Fighter (TEDBF), and early iterations of the projected Advanced Medium Combat Aircraft (AMCA).IAF veterans warned that if at this stage, this GE power pack became collateral damage to the tariff issue, it would have ‘serious ramifications’ for the Force, that faces a serious drawdown of its fighter squadrons, from a sanctioned strength of 42.2 to merely 29, after two legacy MiG-21 squadrons were scheduled for retirement next month in Chandigarh.More recently, delays by GE in delivering its F404-IN20 engines for the upgraded Tejas Mk1A by over a year, had seriously stalled the fighters’ production and affected the IAF’s operational efficiency. Under a $716 million deal inked in August 2021, GE was to supply 99 engines to HAL beginning March 2024.The first engine arrived only in April 2025 as part of the initial batch of 12 engines to be supplied by the year-end, deferred by what GE called “unprecedented supply chain pressures,” including issues with a South Korean component vendor.With timelines disrupted, a besieged HAL activated a contingency plan – repurposing Category B (used) engines for flight tests and quality checks for the Mk1A fighter. But despite that, no Mk1A aircraft had yet been delivered to the IAF, provoking biting criticism from Air Chief Marshal A.P. Singh, who, at the CII Annual Business Summit on May 29, remarked that he could not recall a single HAL project being delivered on time.Alongside, India’s $3.5 billion deal for 31 General Atomics MQ-9B SeaGuardian/Predator unmanned aerial vehicles (UAVs) signed in late 2024, included plans for their local assembly with 15–30% indigenous components and a global Maintenance, Repair & Overhaul (MRO) hub, both of which remain in limbo. The IN, which had fronted the MQ-9B buy, now finds itself navigating a ‘delicate zone’, where political optics over tariffs and trade imbalances could shape final decisions in the military dimension, said a senior naval officer, requesting anonymity.‘Souring trade’ environment likely to ‘unfavourably’ impact defence cooperation frameworksAlso under discussion between Delhi and Washington was the joint development and licensed production of Raytheon-Lockheed Martin Javelin anti-tank guided missile (ATGM) systems and the General Dynamics Stryker infantry combat vehicle (ICV). And though still in their early stages, progressing both projects would necessitate prolonged and complex negotiations, especially around intellectual property rights and cost-sharing. On even these, security officials in Delhi feared a downturn in the broader US-India economic relationship, could lead either to stalling momentum, or force a scaling down of ambitions, or even abandonment.Even a potential follow-on order for additional Boeing AH-64E Apache helicopters-meant to augment the six currently being delivered – after extended delays – to the Army Aviation Corps (AAC), could be jeopardised by the tariff debacle. The AAC has long sought more Apache’s to bolster its attack capabilities for mechanised formations, but insiders said this requirement was now under ‘serious review’ in the face of rising trade tensions.Likewise, the possible procurement of six more P-8I Poseidon maritime surveillance aircraft to boost the IN’s existing fleet of 12 such platforms might not face termination, but could encounter ‘headwinds’ in securing US Congressional approval or in contracting timelines, or even both. Besides, P-8I aircraft include sensitive components and export-controlled technology, making them particularly vulnerable to US bureaucratic and political roadblocks if tensions over tariffs worsen.Indian officials were further concerned over how the ‘souring trade’ environment was likely to ‘unfavourably’ impact defence cooperation frameworks like the India-US Defence Acceleration Ecosystem (INDUS-X) and the associated Initiative on Critical and Emerging Technologies (iCET), both established in 2023.Led by the National Security Councils of both countries, the iCET aimed to facilitate the development and co-production of critical emerging technologies across defence, space, and next-generation telecommunications, including 6G networks. It also encompassed the military employment of Artificial Intelligence (AI), developing semiconductors, and a wide array of advanced engineering, scientific, and biotech projects.INDUS-X, on the other hand, was a joint initiative of the U.S. Department of Defense and India’s MoD under the broader iCET framework. It was intended to focus specifically on defence innovation and start-up collaborations, targeting the co-development of cutting-edge dual-use technologies like AI, quantum computing, cyber defence, and unmanned military systems for air, land and maritime domains.“Both ventures are particularly sensitive to trust and reciprocity within their technology ecosystems,” noted a senior veteran Army officer. He warned that proposals for joint manufacture of military equipment for export to third countries under these two pacts could falter if tariff-related tensions escalated between the two governments.Additionally, the optics of the US imposing tariffs just as India increased its Atmanirbhar push for self-reliance in its defence equipment needs, could inflame political sensitivities in both capitals. While formal defence ties may remain intact, the informal trust and pace needed to advance strategic technology partnerships could well fray; a chill in trade negotiations might not result in any deal being summarily scrapped, but it could quietly freeze momentum at a juncture when the security situation in South Asia was in turmoil.The onus lies on the USA cross-section of analysts, however, believed that neither side wanted the defence and strategic sector to become a casualty of what was essentially a trade dispute.In the past, officials in Washington and Delhi had managed to effectively ‘ringfence’ security cooperation from broader economic friction, driven largely by shared concerns over an increasingly assertive China, Indo-Pacific maritime stability, counter-terrorism collaboration, and intelligence sharing.They further said that historically, India – U.S. defence cooperation had operated in a silo, largely insulated from trade headwinds; but that aspect now seemed to be eroding. Furthermore, India’s continuing Russian oil and materiel imports could well lead Trump to reassess – and overhaul – its military ties and deals with Delhi.Conversely, military sources said this depended on how deftly both sides compartmentalised trade tensions from defence collaboration and shared strategic goals like countering a militaristic China, securing the Indian Ocean Region, and advancing the Quad, which included Australia and Japan.“But, if President Trump insists on leveraging tariffs to extract defence concessions, India may be forced to recalibrate its options,” said the earlier-mentioned IN officer. And though it may not end up ‘dumping’ the US as a defence partner, it could be forced to diversify further – towards France, Israel, Germany, and South Korea, amongst others – and considerably retard defence ties Washington.Hence, the onus now lies on the US to firewall defence cooperation from trade discord – or risk pushing India, once again, back into the familiar and ever-waiting embrace of the Russian bear.