NATO has launched the Steadfast Duel 26 command-post exercise under an Article 5 scenario. Military and civilian representatives from all 32 allies are taking part.
The exercise runs from 6 to 15 October 2026. It is NATO’s largest computer-based command-post drill this year: headquarters are practising command and control across several domains — land, sea, air, space and cyberspace. It is led by NATO’s Joint Warfare Centre in Norway, in cooperation with United States European Command.
Тhis is the first NATO Article 5 exercise involving all 32 members, including Finland and Sweden. Article 5 of the North Atlantic Treaty states that an armed attack against one ally is considered an attack against all. The exercise is not an actual invocation of the article; it rehearses command procedures and defence plans for such a scenario.
General Ingo Gerhartz, commander of NATO’s Allied Joint Force Command Brunssum, said the modern battlefield is no longer three-dimensional and that defending the Alliance requires operating across every domain, including space and cyberspace.
Estonia is participating as a national command element. Major General Vahur Karus, commander of the Estonian Defence Forces Headquarters, called Steadfast Duel a key exercise for NATO command structures: the country is practising its own defence plans together with the Alliance and neighbouring states.
In parallel, from 6 to 15 October, U.S. Army Europe and Africa are running the linked Avenger Triad 26 command exercise in France, Germany, the Netherlands and Poland. About 4,000 troops are involved; the scenario includes more than 2.2 million notional forces — a modelling figure, not the number of troops deployed.
