Law and defence: Vasco Xavier Mesquita argues for a new strategic role for lawyers in European security

Law has ceased to be a mere regulatory instrument and has become a central piece of European defence and sovereignty. This is the thesis put forward by Vasco Xavier Mesquita, partner at Morais Leitão, in an opinion article published in ECO, where he argues that, in a context of hybrid threats, cyberattacks and technological transformation, the lawyer has moved from bureaucratic obstacle to indispensable strategic ally.

For decades, defence was a territory reserved for the military, industry players in the sector and political decision-makers, with the lawyer's role being, at most, to ensure compliance with procurement rules, treaties and limits. Recent events, the author maintains, show that law has ceased to be an accessory to defence and has become its backbone. War has changed and is no longer fought only on the battlefield, but in computer networks, media narratives, supply chains and investment decisions. Hybrid threats, which combine conventional military operations with cyberattacks, disinformation, economic espionage and institutional subversion, have rendered obsolete the traditional separation between internal and external security.

The structural tension in the European defence system

Vasco Xavier Mesquita identifies a fundamental contradiction at the heart of the European defence system. The European Union maintains a public procurement framework designed to guarantee competition, transparency and equal treatment, yet simultaneously sends a political message geared towards strategic autonomy and technological sovereignty, with a demand for speed that the current system cannot support. For the Morais Leitão partner, the harmonisation of defence procurement rules, convergence on dual-use technologies and the creation of legally robust intelligence-sharing mechanisms are essential conditions for European defence integration to move from rhetoric to operational reality.

Defence is increasingly software, and procurement law must adapt

The author stresses that contemporary defence is, to a large extent, a matter of software, algorithms, artificial intelligence and secure communications, rather than hardware. This reality poses an immediate challenge to public procurement law, whose classic procedures are too slow and too exposed to the risk of technological obsolescence. The answer, he argues, does not lie in lowering control thresholds or abandoning principles of transparency, but in developing more agile legal instruments, such as mechanisms for technological review and updating and public-private partnership models in research and development.

Cyberattacks and the limits of international law

In the article, Vasco Xavier Mesquita addresses the difficulties of providing a legal framework for cyberattacks on critical infrastructure, questioning when a cyberattack amounts to an act of war or triggers the right to collective self-defence under Article 5 of the NATO Treaty. Traditional legal categories, he warns, are being overtaken by facts at an unprecedented pace, which means that adapting the legal order is a strategic necessity rather than a theoretical option.

Portugal at the centre of the reinvention of European public law

Finally, the Morais Leitão partner argues that the defence sector now functions as a laboratory for the reinvention of European public law, and highlights Portugal's singular position, resulting from its Atlantic location, its historical and linguistic relationship with the Portuguese-speaking world and its active participation in NATO. Law, he concludes, can and should be the instrument that transforms this geopolitical position into concrete strategic advantage, with lawyers at the centre of this test.

The opinion article is available here.