Key Takeaways from GLOBSEC Brussels’ Event "NATO Enlargement: The Future of the Open-Door Policy after Finland & Sweden"


On December 7th, Jamie Shea, Amanda Paul, Alena Kudzko, and Benjamin Haddad joined GLOBSEC in Brussels to explore how Sweden and Finland’s accession to NATO will impact the Alliance’s Open-Door Policy, its internal dynamics, and European defence in general.  

Russia’s war in Ukraine has shaken Europe and pushed Finland and Sweden to pursue NATO membership. The two countries rapidly obtained an invitation from the leaders of the Alliance at the Madrid Summit last June. However, this process has so far been effectively blocked by Türkiye and Hungary. GLOBSEC’s debate event explored questions related to the role of inter-ally relationships and domestic politics in the accession process and the evolution of European strategic autonomy alongside a reinforced and larger NATO. 

There was a general agreement that the Alliance is again at the forefront of European defence and has demonstrated its role as the primary security provider in the region. For the most part, its member states remain in favour of the open-door policy, which has allowed the Alliance to expand to more than twice its original size. However, the future of its enlargement remains uncertain. First, NATO has not established a clear definition and delimitation of Europe. In this context, the inclusion or exclusion of potential member states remains a political decision subject to debate and controversies. Second, domestic political issues can impact the accession process. Indeed, Turkish President Erdogan has used the outrage over alleged support to the Kurdish armed movement PKK in Sweden to rally support for himself nationally as his country faces an acute economic crisis. Lastly, member states can use their support for membership as a bargaining chip in exchange for political or financial benefits in entirely unrelated fields. Internal cohesion and alignment are essential to limit such transactions.  

Ukraine’s candidacy to join the Alliance illustrates that countries in Central and Eastern Europe consider NATO membership essential in protecting their existence. Article 5 of the North Atlantic Treaty provides security guarantees that have attracted many nations to the organisation and which have long seen Russia as the main threat to their survival. In this context, strategic ambiguity and ambiguous messages from the West have been denounced as they lead to misunderstandings between Allies, contribute to reducing trust in common defence and potentially encourage aggression from outside actors like Russia.  

In the meantime, Europe is increasingly aware of its own vulnerability and is deepening its defence investments. European strategic autonomy efforts aim to increase the capacity of the region to be a more active security provider within the Alliance. Moreover, under Trump, US diplomacy has become less predictable. For a stronger Alliance and transatlantic cooperation, Europe and the United States should increase dialogue and cooperation in the security and economic domain. NATO’s door remains open, but further enlargements will have to be prepared by more vigorous efforts at timely and frank debate, as well as by stronger cohesion among the member states.