Legal Interoperability and NATO Convergence

A Strategic Look at the Role of the JAG Corps in Great Power Competition

By CW4 Jairo Parra, Judge Advocate General’s Corps

Article published on: February 1, 2026 in the Warrant Officer Journal Winter 2026 issue

Read Time: < 4 mins

The concept of convergence – an outcome created by the concerted synchronization and integration of effects across land, air, maritime, cyber, and space from multiple echelons against combinations of decisive points in any domain to create the impact against a system, formation, decision maker, or in a specific geographic area (U.S. Department of the Army, 2022) – is central to the U.S. Army’s approach to Multi-Domain Operations (MDO). For NATO, convergence is uniquely complex, requiring not only cross-domain synchronization but also multinational alignment of international law, rules of engagement, and national authorities. Legal interoperability is therefore not a peripheral concern; it is a strategic prerequisite for credibility, deterrence, and operational success that must be achieved through cooperation (see Figure I-1).

In an era marked by intense power competition, the effectiveness of the US-NATO Alliance, and NATO’s multi-domain convergence, hinges not only on military capabilities but also on the ability of its legal advisors (LEGADs) to harmonize divergent national authorities, rules of engagement, international treaties, and the interpretation of international law. The U.S. Army JAG Corps, in partnership with NATO LEGADs, must spearhead the efforts to establish legal interoperability as a strategic enabler of deterrence, credibility, and operational success across the Alliance.

The U.S. Army’s concept of convergence – the agile and integrated employment of effects across land, maritime, air, space, and cyber domains – has emerged as the central component to its approach to Multi-Domain Operations (MDO). In the U.S. context, convergence reflects not only the operational and technical synchronization of capabilities but also the ability to synergize authorities, systems, processes, and expertise to deliver timely and decisive effects of combat power during a crisis (U.S. Department of the Army, 2022). At the NATO level, however, convergence adds additional layers of complexity that must be addressed during the cooperation phase of the Competition Continuum (see Figure I-1). The Alliance must integrate not only across operational domains but also across the sovereign legal frameworks, rules of engagement, doctrine, regulations, and political constraints of thirty-two member states.

In this complex environment, law is not merely a constraint but a strategic enabler. Effective and timely legal support ensures that multinational forces act within domestic and international legal parameters, thereby maintaining legitimacy, credibility, and cohesion. As it pertains to all U.S. branches of government, federal law and policy provide the framework for strategic direction, setting the context, purpose, and tasks for employing the instruments of national power (Department of Defense, 2022). Conversely, divergent interpretations of law and policy amongst NATO members create operational gaps that adversaries can exploit. Russia and China, in particular, have demonstrated an adept use of the current operational environment, military lawyers must spearhead the dialogue among NATO Allies and partners to synchronize legal perspectives, influence policy and statutory developments where possible, and manage divergence when necessary.

Strategic-Level Challenges in NATO Convergence

Cyber Operations – NATO Allies disagree on whether inevitable cyber intrusions and operations constitute an armed conflict attack or an intelligence activity. As discussed by Schiffman (2022), China’s primary method of operation is to reinterpret international law, particularly in the maritime, space, and cyber domains, in ways most favorable to China’s interests and least beneficial to its adversaries. Other near-peer adversaries use the same methods to create dominance in the cyber realm, consistently accomplishing their strategic objectives while remaining below the threshold of armed conflict. Additionally, attribution standards throughout the Alliance vary vastly, and secrecy laws often restrict intelligence sharing, slowing NATO’s ability to converge cyber effects (Aronsson & Swaney, 2022).

Interoperability and Standards – NATO and its allied partners must achieve and sustain interoperability across the technical, procedural, human, operational, and information domains while adapting to emerging technologies and competing international standards. Harmonizing legal frameworks, ensuring compliance with international law, and providing timely and decisive legal advice on sovereignty, ROE, humanitarian and disaster management, and ethical norms to enable seamless multinational operations (Aronsson & Swaney, 2022)

Recommendation: Advancing Legal Interoperability

• Develop NATO Legal Convergence Doctrine. Collaborate and produce a baseline authorities matrix and shared threshold guidance.
• Institutionalize Legal Planning. Include LEGADs in early operational design and employ legal “red teams” in all NATO, multinational, and Joint exercises.
• Expand and Develop Legal Education and Training. Deepen institutional learning in emerging domain law, expand the understanding of doctrine, increase multinational LEGAD exchanges, and develop Legal Centers of Excellence (CoEs) across all Allied and partner nations.
• Strengthening Legal Networks. Empower NATO and partner CoEs and regional legal forums to cultivate interoperability by developing a multinational training curriculum and training aids aimed at achieving NATO convergence.
• Further U.S. JAG Corps Presence and Leadership. Carefully assign leadership, cultivate strategic talent, and maintain presence in key NATO billets and Headquarters to provide and influence U.S. interests throughout the Alliance.

Conclusion

NATO’s ability to converge capabilities across domains in a moment depends on more than technology and synchronizing effects – it depends on the legal interoperability of its member states. Divergent national legal frameworks slow operations, weaken deterrence, and create exploitable seams for adversaries. Conversely, harmonized legal approaches project unity, strengthen legitimacy, enable swift action, and, if necessary, respond to aggression.

The JAG Corps, working alongside NATO LEGADs, must lead this effort. By embedding legal advisors in planning, shaping doctrine, developing and enabling CoE, and building multinational trust networks, they transform law from a constraint into a force multiplier. In the era of great power competition, where adversaries exploit “the grey zone, NATO’s credibility rests not only on military might but also on its ability to act lawfully, cohesively, and decisively.

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