Before Russian President Vladimir Putin launched his invasion of Ukraine, the question of NATO membership was barely part of the political debate in Finland and Sweden. Both countries have a long history of military nonalignment, and although they have gradually pursued closer cooperation with the United States and NATO—and politicians in both countries have long advocated membership—NATO accession was hardly seen as a pressing issue.

Putin’s invasion of Ukraine changed all that. In response to Russian aggression, both countries are reassessing their security policies, and seeking NATO membership is rapidly emerging as the most realistic option. Recent polls show that clear and increasing majorities in both countries support joining the alliance. In addition, both countries have delivered substantial amounts of weapons to Ukraine, including 10,000 man-portable antiarmor weapons from Sweden.

By invading Ukraine, Putin sought not only to bring that country back under its influence but to also change the security order of Europe. On the latter point, he has succeeded—just not in the way he likely intended. Russia’s assault has unified NATO and made its expansion much more likely. If Finland and Sweden join the alliance, as they look poised to do, they will bring substantial new military capabilities, including advanced air and submarine capabilities, that will alter the security architecture of northern Europe and help deter further Russian aggression.

ARMED NEUTRALITY

The Nordic countries are similar to one another in many respects, but they have pursued very different security policies since World War II. To a large degree, these differences reflect the neighbors’ different experiences during the war. Denmark and Norway sought neutrality, but were occupied by Nazi Germany in 1940. Finland initially rebuffed a Soviet invasion in the Winter War of 1939–1940. Later, it found itself fighting on Hitler’s side until it could extricate itself from the war. Sweden alone among Nordic countries escaped the horrors of war and occupation with a policy of neutrality designed to ensure its survival. That this policy succeeded was largely because Hitler’s military calculus didn’t require the acquisition of Swedish territory; he could achieve his objectives in the area by other means.

After the war, Sweden contemplated forming a Nordic defense union with Denmark and Norway. But negotiations broke down, mainly because Norway believed that only an alliance with the Anglo-Saxon maritime powers could guarantee its security. Sweden wasn’t ready for such alliance, in part because of the situation in Finland. Coming out of the war, Finland—which had been one country with Sweden for six centuries until 1809—was in a precarious position. It had lost its second biggest city, Viborg, and been forced to accept a treaty of friendship with the Soviet Union. It had restrictions on its armed forces and a Soviet military base immediately to the west of the capital, Helsinki. The Soviets also dominated the Allied Control Commission charged with overseeing the country in the immediate postwar years.

Russia’s assault has unified NATO and made its expansion much more likely.

For Sweden, ensuring that Finland didn’t fall under the yoke of the Soviets was a vital interest. Swedish leaders believed that any move toward a broader Western alliance would make Finland’s position even more precarious. And although they avoided saying so in public, this consideration was the main reason for Sweden’s policy of armed neutrality during the Cold War.

But neutrality did not mean neglect of the armed forces. Throughout the Cold War, Sweden maintained robust military forces, including an air force that for a time was seen as the fourth strongest in the world. Its official policy was one of strict military nonalignment, but it also made concealed preparations to cooperate with the United States and NATO in the event of war, and its stance was generally seen as conducive to Western security interests in the region.

A POLITICAL EARTHQUAKE

With the fall of the Soviet Union, the security situation in northern Europe changed dramatically. Finland, which had gradually consolidated its position as an independent Nordic democracy, could now throw off the last shackles of the postwar period. The three Baltic states—Estonia, Latvia, and Lithuania—had broken loose from the Soviet Union even before its formal demise. And in 1995, Finland and Sweden joined the European Union, a move that both countries had previously deemed impossible because of their policies of neutrality.

For those two countries, joining the EU meant ditching the concept of neutrality. But doing so did not immediately spark discussions about joining NATO. These were the years of the 1989 Paris Charter, which sought to build a European security order that included Russia, and of the conferences that led to the establishment of the Organization for Security and Cooperation in Europe. Finland and Sweden both held out hope that they would be able to develop a constructive security relationship with a democratic and reforming Russia. Even after Estonia, Latvia, and Lithuania gained membership in NATO and the EU more than a decade later, there was little debate in either Sweden or Finland about reconsidering nonaligned military status.

Starting in 2008, however, things in Moscow began to change markedly. Russia’s invasion of Georgia that year revealed that its threshold for using military force to pursue its political objectives was substantially lower than many had thought, and a distinctly revisionist tone started to creep into Moscow’s policy pronouncements. These trends accelerated dramatically in 2014, when Russia sought to prevent Ukraine from pursuing an association agreement with the European Union and to dismember the country through military aggression.

Russia’s full-scale invasion of Ukraine this year is drastically changing the geopolitical landscape once again. Putin’s immediate aim is to subdue Ukraine, but he is also waging a war against the West. The Russian leader and his acolytes have made it clear that they wish to replace the post-1989 security order in Europe with arrangements that impinge on the sovereignty of other countries. And just as the collapse of the Soviet Union led Sweden and Finland to reconsider their relationships to Europe, the current political earthquake has prompted them to reconsider fundamental elements of their security policies, including their relationships to NATO.

Putin’s immediate aim is to subdue Ukraine, but he is also waging a war against the West.

The outcome of the war in Ukraine is still unknown. It is impossible to predict what kind of country Russia will be in the decades ahead, but what is likely to emerge is a country that is both weaker in economic and military terms and more desperate and dangerous in political terms. The Putin regime—whether he or one of his associates is at the helm—is unlikely to give up its imperial ambitions as long as it remains in power.

This reality fundamentally changes the security considerations of both Helsinki and Stockholm. Increased defense spending is clearly one part of the answer to the new security situation. Both Sweden and Denmark have announced that they will increase their defense spending to two percent of GDP, Sweden by 2028. Norway, Finland, and the three Baltic states are more or less there already. Since 2014, Finland and Sweden have also dramatically expanded their military cooperation with NATO, the United States, and the United Kingdom, creating a foundation for further cooperative steps. For more than a decade now, the Swedish, Finnish, and Norwegian air forces have been training together on close to a weekly basis.

But just strengthening defense capabilities is no longer seen as enough, which is why NATO accession is rapidly becoming a reality. Both Finland and Sweden have considered alternatives. The two governments sent a letter to all other EU members, reminding them of the solidarity provision in Paragraph 42.7 of the EU treaties, which is similar to the collective defense clause in Article 5 of the NATO Charter. Important initiatives to strengthen EU defense and security policy integration are underway, but as far as territorial defense is concerned, duplicating the institutions and command structures of NATO would make little sense and won’t happen. And of course, the EU does not include the two nations of greatest military relevance to northern Europe—the United States isn’t a member for obvious reasons, and the United Kingdom isn’t one for regrettable reasons.

Both Sweden and Finland are likely to continue to pursue measures that would make the EU into a stronger security alliance, but when it comes to territorial defense, there is simply no alternative to NATO. That has been the clear conclusion of the independent processes Helsinki and Stockholm have undertaken to evaluate alternatives.

Both Finland and Sweden will indicate their interest in joining the alliance well before the late-June NATO summit in Madrid. NATO Secretary-General Jens Stoltenberg has said that he foresees a fairly rapid accession process in light of the high degree of military integration that Finland and Sweden have already achieved, but ratification by all 30 member states will still take time. Both countries hope that ratification, particularly in the U.S. Senate, can be fairly rapid and that existing NATO members will be ready to jointly deter any possible Russian provocations between the start of the accession process and its likely completion in 2023.

A CHANGED LANDSCAPE

When Finland and Sweden join NATO, the security architecture of northern Europe will change. Each country brings considerable military capabilities to the alliance: Finland maintains an army with very substantial reserves, and Sweden has strong air and naval forces, particularly submarine forces. With Sweden’s advanced Gripen fighters added to the F35s now ordered or under delivery to Norway, Denmark, and Finland, more than 250 highly modern fighters will be available in the region as a whole. Operated together, they will be a substantial force.

Integrated control of the entire area will make defense of Estonia, Latvia, and Lithuania easier, since Swedish territory and airspace in particular are important for such efforts. This will strengthen deterrence and make a conflict there less likely, according to studies published by both Sweden and Finland. But perhaps the most important consequence of Finnish and Swedish accession to NATO would be to increase the alliance’s political strength as the pillar of the defense of Europe and the transatlantic area. Both countries will help facilitate deeper coordination between the EU and NATO, thus contributing to better burden sharing across the Atlantic—a goal of increasing importance in light of the greater demands placed on the United States by the security situation in East Asia.

Even as they join NATO, Finland and Sweden are likely to take care not to unduly provoke Russia by threatening its long-term security concerns. Norway, which has successfully combined strong military integration in NATO with a policy of reassurance toward Russia, could well serve as a model. The Russian forces and facilities in the Kola Peninsula—in the immediate vicinity of both Norwegian and Finnish territory—are of fundamental importance to Russia’s second-strike strategic nuclear capabilities, and Finland is, of course, close to the major population center and industrial hub of St. Petersburg. Partly for these reasons, neither Finland nor Sweden is likely to seek any permanent basing of major NATO units in their territory, and both are likely to have the same reservations about housing nuclear weapons as Denmark and Norway expressed when they joined the alliance.

As the NATO summit in Madrid approaches, the alliance will have to consider Finland’s and Sweden’s requests for rapid accession. This should be seen not only as a way to strengthen the stability of the Nordic and Baltic areas but also as an opportunity to strengthen the alliance as a whole at a time when Russia’s military aggression has made that imperative.

You are reading a free article.

Subscribe to Foreign Affairs to get unlimited access.

  • Paywall-free reading of new articles and a century of archives
  • Unlock access to iOS/Android apps to save editions for offline reading
  • Six issues a year in print, online, and audio editions
Subscribe Now
  • CARL BILDT is Co-Chair of the European Council on Foreign Relations and former Prime Minister and Foreign Minister of Sweden.
  • More By Carl Bildt