With Sweden in, NATO must now deliver on its wider transformation agenda.

For the last 18 months, NATO watchers have talked about Sweden as a soon-to-be NATO member, framing its accession as all but inevitable. Now that Hungary has ratified Sweden’s application, the country, one of NATO’s closest partners for decades, can count itself as a full-fledged alliance member once lingering formalities are completed.

The process for bringing Sweden in was expedited compared to pre-2022 standards, but it still took longer than the transatlantic policy community expected due to political hostage-taking by Hungary and Türkiye. Nonetheless, for Sweden, the clear prospect of membership served as a form of interim security guarantee. As NATO thinks about future prospective members, including Ukraine, this is crucial.

The extended ratification period was undoubtedly less than optimal, but it gave both sides time to plan for and start operationalizing Sweden’s contributions to NATO’s updated domain-specific and regional defense plans. These underpin a transformation through, in part, a strategic integration of forces under the leadership of the Supreme Allied Commander Europe (SACEUR).

In the interim, Sweden made critical and targeted investments in its defense industry, infrastructure, and interoperability, which will be essential to NATO’s overall defense, but especially its posture in the Baltic Sea and Arctic theaters. The membership delay also did not stop the country from participating in Steadfast Defender 24, NATO’s largest exercise since the Cold War. Looking ahead, Sweden, having closely monitored Finland’s integration process, is now well positioned to implement valuable lessons learned. All these factors will expedite the country’s integration into the alliance’s command structure.

Sweden specifically brings to NATO a formidable air force and submarines able to operate in the shallow waters. It also serves as a critical link and transit route to enable military mobility, reinforce Norway and Finland, and defend NATO’s northern flank. Sweden’s “Total Defense” concept, like other Nordic countries’ whole-of-society approaches to security, also serves as powerful example of building societal trust, cohesion, and resilience to complex and prolonged crises. This holds valuable lessons for other alliance members and NATO as a whole.

NATO faces a decisive 2024. Important elections in the United States and Europe loom as the security situation in Ukraine deteriorates. The alliance’s consensus structure makes fast decision-making hard, especially when not all members feel an existential threat and see political advantage in stalling. But the threat that NATO faces from those who seek to undermine its power—Russian President Vladimir Putin and his allies chief among them—is existential, and the alliance cannot afford to allow infighting to undermine deterrence and resolve. Ahead of NATO’s 75th anniversary summit in Washington, DC this summer, all the alliance’s 32 members need to build on the success of the Nordic enlargement by pulling together to implement their ambitious transformation agenda and enter the next decade stronger and more united than ever.