Explained | Sweden joins NATO — What does this mean for Ukraine and the alliance?

For a few years now, Turkey's relationship with NATO has been nuanced and strained. Turkey's objections to Sweden's accession were ostensibly connected to its concerns over Sweden's policy towards the Kurdistan Workers' Party, or PKK. Turkey has accused Sweden of hosting Kurdish militants. NATO has acknowledged this as a legitimate security concern and Sweden has made concessions as part of its journey towards NATO.

The material driver of the agreement, however, may always have been a carrot being dangled by the US. American President Joe Biden now appears to be moving forward with plans to transfer F-16 fighter jets to Turkey — a deal that appears to have been unlocked by Erdogan's changed stance on Sweden. But it is often the case that a host of surrounding deals and suggestions of deals can help facilitate movement at NATO. Everyone, including Turkey, now seems able to sell the developments as a win to their constituents back home.

Sweden joining NATO holds significant political, strategic, and defensive planning implications. Strategically, Sweden and Finland can now seamlessly collaborate with other NATO allies to plan for collective defence. This integration of strategic plans is particularly valuable given Finland's extensive border with Russia and Sweden's control of critical terrain like the Baltic Sea island of Gotland. The accession also facilitates increased strategic interoperability and coordination among NATO allies.

NATO allies will now engage in unprecedented cooperation and transparency regarding defence planning. Finland and Sweden will undergo bilateral and multilateral examinations as part of NATO's defence planning process, working with the alliance's international secretariat and all allies. Their defence investments will be scrutinized, while Finland has already experienced a significant increase in defence spending leading up to and following its NATO accession. Similar increases in defence investment are expected from Sweden, as alliance norms and peer pressure often drive such changes.

While Sweden's accession to NATO is a significant development, it does not immediately impact Ukraine's membership aspirations. The ongoing war in Ukraine and its unpredictable outcome make it unlikely for NATO to offer Ukraine a membership action plan in the near future. The expansion of NATO to include Sweden, however, strengthens the alliance's position and demonstrates its commitment to collective defence in the face of Russian aggression.