When a company invents a new drone navigation system, a quantum-hardened encryption chip, or an AI-powered autonomous vehicle, the instinct is to file a patent. Although it should not make a difference, in periods of heightened geopolitical tension, that same filing triggers a government secrecy procedure that freezes the application, prohibits foreign disclosure, and imposes criminal liability for violations. This is not hypothetical – it is the legal reality in every NATO member state, albeit under strikingly different rules.
A Cold War framework still in force
The legal foundation dates to September 21 1960, when 12 founding NATO member states signed the Agreement for the Mutual Safeguarding of Secrecy of Inventions Relating to Defence and for Which Applications for Patents Have Been Made in Paris. Its purpose was simple: if one NATO government declared a patent application secret on national-defence grounds, all other signatory states were obliged to recognise and maintain that secrecy for any corresponding application filed in their territory. Attorneys handling patent applications declared secret on national-defence grounds were required to have a security clearance from their national government.
After the fall of the Berlin Wall in 1989, the perceived urgency of this agreement faded. National implementing laws lost political priority and fell out of synchronisation with the modernised intellectual property (IP) landscape – European patent applications, Patent Cooperation Treaty filings, and digital filing systems had all overtaken the administrative infrastructure that was available in the early years of the agreement. The current geopolitical environment – with active conflicts in Europe and rapid militarisation of dual-use technologies such as AI, quantum computing, drones, and cybersecurity – has rendered this neglect a practical problem.
Four countries, four approaches
A comparative analysis of Belgium, the Netherlands, France, and the US reveals a landscape of dramatic divergence across four key dimensions.
Parameter | Belgium | Netherlands | France | US |
Primary legislation | Act of 10 January 1955 | Rijksoctrooiwet 1995, articles 40–46 | The French Intellectual Property Code, Article L612-8/9; the Penal Code; the Defence Code, Article L2332-6; General Interministerial Instruction No. 1300/SGDN/PSE/SSD on the protection of national defence secrecy, of August 9 2021; and Interministerial Instruction No. 9062/DN/CAB, of February 13 1973 | Title 35 of the US Code, sections 181–188 |
Who must file nationally first | Belgian persons or residents | Not specified | French citizens as applicants or inventors | Any person for any invention made/developed in the US |
Guidance on eligible technologies for applicants and attorneys | None | None | Guide des usages des acteurs de la propriété intellectuelle en matière de sécurité et de défense (National Industrial Property Institute) | - |
Foreign filing licence available | No | No | Yes
| Yes (auto-requested at filing) |
Cleared patent attorneys | None available | No information available | No information available | No information available |
The trigger criterion is the most fundamental divergence. Belgium and the Netherlands provide no guidance to applicants about which technologies fall under the secrecy obligation – a legally precarious position for companies innovating in defence-related technology, as well as for patent attorneys, since attorneys in these countries are to decide whether European priority applications need to be filed through the respective national office. France automatically forwards all applications to the Ministry of Defence within 15 days, whereas the US reviews every application instantaneously and issues a foreign filing licence as a matter of course. Hence, in France and in the US, that uncertainty is avoided.
The foreign filing licence gap is perhaps the most operationally critical issue. Belgium and the Netherlands offer no formal procedure, allowing an invention’s eligibility check to fall under the applicable law.
The clearance paradox is equally striking. In Belgium, it is publicly known that there are currently no patent attorneys with government security clearance. A founding NATO member state has, in effect, no domestic legal infrastructure capable of handling its own classified patent applications. The other founding NATO member states, the Netherlands, France, and the US, offer no public information on the matter.
The number of applications placed under secrecy is rising sharply
Among the four countries examined, the US operates by far the most statistically documented secrecy regime, with data published annually by the Federation of American Scientists. The numbers tell a clear story of escalation from 61 new secrecy orders in 2021 to 356 in 2024 and 102 in 2025. The total of US applications kept under a secrecy order is continuously increasing, the total number being 6,471 at the end of 2025.
The European dimension
The European Patent Convention (EPC) accommodates national secrecy regimes through Article 75 but creates no harmonised framework for handling them. On the contrary, Rule 37 of the EPC governs the forwarding of European applications from national offices to the EPO. An EPO-administered mechanism to handle classified applications with cleared examiners and defined interfaces with national defence ministries would provide a structural solution but would require treaty-level modification and would need to navigate the misalignment between EU and NATO membership.
At NATO level
From NATO itself, all remains silent. A consolidated NATO foreign filing licence covering all member states at once – issued by a NATO-based agency – does not currently exist, no information on any possible thoughts in this direction is available, and it hence does not appear to be a near-term priority.
Summary: a fragmented landscape
The comparative analysis reveals a landscape of significant fragmentation, outdated infrastructure, and growing operational risk at precisely the moment when defence-related innovation is accelerating most rapidly.
The complete absence of a foreign filing licence mechanism, combined with no applicant guidance and no cleared or not identified attorneys, creates a systemic lack of a reliable legal pathway to international patent protection for defence-sensitive inventions.
Building a multi-jurisdictional patent portfolio covering a defence-sensitive invention requires navigating various distinct legal regimes with no cross-border coordination mechanism between NATO member states and no EU-level safety net. This demands precisely the right combination of national experts working in concert. Existing frameworks are neither equipped nor sufficiently coordinated to handle the present expansion of potentially secrecy-eligible applications without significant legislative updates and international coordination.
Whether and for which defence-related inventions an attorney is willing to cooperate ultimately remains a personal (ethics-related) choice. But this choice should be made with full awareness of a legal landscape that is simultaneously critical, fragmented, and largely under-discussed in the IP community.
