Trace the evolution of India-US defence cooperation through bilateral military exercises since 2004.

Exercise Yudh Abhyas, conducted annually since 2004 with the venue alternating between India and the USA, is the clearest running record of how bilateral defence ties moved from cautious familiarisation to an institutionalised, decade-long partnership [2][3].

Phase I (2004-13): Foundation through familiarisation

• The exercise began as an Army-to-Army serial, its stated aim confined to exchange of best practices and Tactics, Techniques and Procedures (TTPs) [2][3].
• Alternating hosting built reciprocity and trust without binding commitments — confidence-building rather than combined warfighting [3].

Phase II (2014-23): Widening scope and roles

• The 2022 Uttarakhand edition trained an integrated battle group under a UN Chapter VII mandate, adding peacekeeping and HADR content [4].
• The partnership segmented into role-specific serials — Vajra Prahar for special forces — reflecting widening functional coverage [6].

Phase III (2024-26): Scale, terrain and institutionalisation

• The 20th edition (9-22 September 2024) at Mahajan Field Firing Ranges, Rajasthan, marked a stated rise in troop strength, equipment and complexity [2].
• The 2025 edition moved to Fort Wainwright, Alaska, a sub-Arctic node, with drills spanning mountain warfare, UAS and counter-UAS [3].
• The 2026 edition at Auli and Mahajan introduces a two-theatre format, pairing Himalayan high-altitude with desert terrain in a single edition [1].
• It is the first India-hosted edition under the 10-year framework for the US-India Major Defence Partnership, signed on 31 October 2025 at Kuala Lumpur [5].

Continuing ceiling

• The declared objective still stops at TTP exchange, short of combined planning, logistics or command [2][3].
• Army-only design and divergent inventories limit procedural convergence from becoming full equipment interoperability.

Thus the trajectory runs from tactical familiarisation to terrain-matched, framework-backed cooperation, while remaining deliberately non-binding. Sustaining this calibrated path — deepening training value without diluting strategic autonomy — offers India a workable model for partnering major powers on its own terms.