Sweden is Finland’s Closest Partner

When Finland’s then-Foreign Minister Pekka Haavisto deposited the instrument of accession with the United States Secretary of State, Anthony Blinken, on 4 April 2024, it was Finland’s very first official act as a NATO member to hand over the ratification documents of Sweden’s accession – seconds after becoming a member. The fact that Sweden’s accession took longer than Finland’s cast a shadow on Finland’s first year in NATO. Then-President Sauli Niinistö remarked on it in his statement on Finland’s accession in April 2023: “Finland’s NATO membership is not complete without that of Sweden,” and it became a frequently repeated statement by Finnish political leaders in the period of 11 months between Finland and Sweden’s NATO accession.

Why Sweden Matters (So Much)

Therefore, it was an occasion for a deep sigh of relief in Finland in early March 2024 when Sweden’s NATO membership was finally fully ratified, after Hungary, the last NATO member to hold out its ratification, completed the task. Reactions by Finnish officials and political leadership on the day of Sweden’s accession ceremony on 7 March were overjoyed: the Ministry of Foreign Affairs, for example, posted a congratulatory video on the social media platform X (previously Twitter), with Finland’s Minister for Foreign Affairs Elina Valtonen waving a Swedish flag and the song “Den glider in,” known from the 1995 ice hockey world championship finals where Finland beat Sweden, playing in the background. On the day Sweden became a NATO member, Finland’s membership was completed too.

Finland’s geographical location is characterized by the opposite nature of its main neighbors: on the one side, the long history of oppression and wars with Russia, which is also currently waging a brutal war on another neighbor; on the other side, Sweden that has not waged wars since 1814. Furthermore, belonging to the Nordic group has been a window to the West for Finland after the World Wars, and the historical and linguistic connections to Sweden have facilitated Finland’s identity as a Nordic country. It explains why Finns tend to follow political, economic, and societal developments in Sweden in a manner bordering on obsessive and why it is perfectly logical in Finnish public debates to cite Sweden as both the better and the worse example, depending on the point of view. For Finland’s post-World War development, the orientation towards and rapprochement with Sweden has been an important facilitator in the process of creating distance from Russia and the Soviet Union and building Finland into a successful Nordic welfare state. As Bergquist et al. (2016) put it, “the mere existence of Sweden was of immense significance for post-war Finland as a neighbor, trade partner, and a social model.”

Finland and Sweden: Connected by History

The joint NATO accession process and the aspiration to join the alliance together has brought Finland and Sweden closer in the vital policy field of security and defense than the two countries probably ever have been since the Kingdom of Sweden lost Finland, then the eastern part of the kingdom, to the Russian empire in 1809. Finland’s Minister of European Affairs and Ownership Steering, Anders Adlercreutz, published a video on the social media platform X on the day of Sweden’s NATO accession, telling a personal story of that war: his relative, Major General Carl Johan Adlercreutz, had led the Swedish forces in the battle of Oravais where Sweden suffered a decisive defeat against the Russian Empire. As it became clear that Sweden would lose Finland to Russia, the officers under Major General Adlercreutz decided to open the uppermost button in their uniform sleeves, not to be closed until Finland and Sweden were reunited. On the day Sweden became a NATO member, Minister Adlercreutz symbolically closed the uppermost button of his suit sleeves in the video.

A more recent unifying historical factor between Finland and Sweden was that both remained neutral during the Cold War and continued the policy of military non-alignment after the fall of the Soviet Union until Russia’s full-scale war of aggression against Ukraine in 2022. However, the drivers of both countries’ neutrality policies were vastly different. While it is not possible to give a comprehensive account of Finland and Sweden’s neutrality policies here, a brief overview of the important links between Finland and Sweden during the Cold War neutrality is given. It is relevant to understand the different reasons why Finland and Sweden remained neutral during the Cold War, to better understand why it took 30 years after the Cold War to make the decision to join NATO.

Sweden’s Neutrality and the “Finnish Question”

For Sweden, the question of NATO membership has ostensibly been politically linked to Finland. At the end of WWII, Sweden was faced with a choice as spheres of influence were being demarcated: To join the Western NATO bloc or remain neutral. After the attempt to establish a Scandinavian Defence Union with Norway and Denmark failed in 1949 and the two others joined NATO as founding members, Sweden kept up its neutrality that it had managed to uphold also during the Second World War. Part of the argument was that if Sweden joined NATO along with Norway and Denmark, it would leave Finland alone to face the Soviet Union. In such a case, it was argued in Sweden at the time, Finland would almost certainly have fallen entirely within the Soviet sphere of influence, possibly even being annexed, as Moscow would not have accepted a fully NATO-dominated Nordic region. Indeed, Finland was already identified as within the Soviet sphere of influence in the Molotov-Ribbentrop pact between the Soviet Union and Nazi Germany and had just fought for its independence in the Winter War 1939–40. Thus, Swedish leaders believed that their neutrality would help Finland maintain its independence, creating a larger buffer between the Soviet bloc and NATO.

It was also in accordance with the idea of a “Nordic balance,” as formulated by Arne Olav Brundtland in 1966: Denmark and Sweden in the Western bloc, Sweden’s “well-armed neutrality,” and Finland’s neutrality with “arms control” in the form of the Finno-Soviet Friendship Treaty of 1948. As Risto E J Penttilä describes the mechanism, “if the Soviet Union were to tighten its grip on Finland, Norway and Denmark would welcome permanent NATO bases and nuclear weapons on their territory. And vice versa: if NATO were to increase its presence in Norway and Denmark, Moscow would tighten its grip on Finland. Both sides refrained from making such moves.”

However, although the Swedish rhetoric about neutrality became increasingly fervent on the political level during the Cold War decades and Sweden pursued an active, normative “third way” foreign policy with a strong focus on the so-called Third World between the blocs, Sweden simultaneously cooperated quite extensively and to an increasing degree with its NATO neighbors Norway and Denmark on the military level. As an incentive to give up its nuclear weapons program, the United States even offered Sweden secret security guarantees. For Finland, in contrast, neutrality during the Cold War was a pragmatic rather than ideological choice that served to emphasize Finland’s independent status as a non-Soviet bloc country, thereby increasing Finland’s room for maneuver that was limited by the Finno-Russian Friendship Treaty. NATO membership was out of the question for Finland in any case, as the treaty stipulated that neither party would join alliances “hostile to either party to the treaty.” The treaty also specifically names Germany as a potentially hostile country, and West Germany was taken into NATO in 1955. Neutrality (as well as sauna) helped Finland fend off Soviet suggestions to hold military exercises together in the 1970s. After the Cold War, Finland maintained military non-alignment for as long as it served the practical purpose of avoiding costly tensions at the long border with Russia. The so-called “NATO option,” meaning that Finland reserved the right to reconsider its non-alignment, should the security environment change, served a similar purpose as the emphasis on neutrality during the Cold War, and was an important response to the regular Russian threats about consequences of a Finnish NATO accession. Putin’s demand on NATO not to accept new members – including Finland and Sweden – in December 2021 directly undermined Finland’s NATO option policy, which Finland’s President Sauli Niinistö addressed in his 2022 new year’s speech, reminding of Finland’s sovereign right and freedom of choice regarding NATO membership.

NATO Membership: Not a Question of If, but When

After the end of the Cold War, Sweden did not seek NATO membership either but otherwise followed the general trend – and NATO doctrine – of a focus on crisis management and professionalization of forces away from the Cold War conscription army to an expeditionary force model. A policy change began in the 2010s, when Sweden stated readiness to give and receive military assistance in case of an attack on EU and Nordic partners. Sweden began investing in increasingly close defense ties to Finland, its Nordic neighbors, and NATO partners – intensively so since Russia’s annexation of Crimea in 2014. Both Finland and Sweden had been pursuing a close partnership with NATO already since the 1990s, by joining the Partnership for Peace in 1994. In 2014, both received a status upgrade to Enhanced Opportunity Partners.

Finland and Sweden have also been among the most active partners of NATO and contributed to NATO’s missions and operations, starting with the NATO-led peacekeeping force in Bosnia and Herzegovina in 1995 (Sweden)/1996 (Finland), Afghanistan (Sweden 2003–2014 and in a supporting role until 2021, Finland 2002–2021), Iraq, Kosovo and Libya (Sweden). Both have also participated in the enhanced NATO Response Force (NRF) and signed a memorandum of understanding on Host Nation Support. Thus, Finland and Sweden had reached the “plateau” of the highest possible level of partnership with NATO, with full membership as the only remaining logical step.

What comes to national military power, Sweden has displayed a tendency to swing from one extreme to the other, going from a weak military capability before the Second World War into building one of the world’s largest air forces during the Cold War, then radically scaling down the armed forces in the 1990s and 2000s. Now Sweden is swinging back again, with the latest Defense Commission recommendation – reportedly inspired by Finland’s new President Alexander Stubb’s recommendation to “talk less and prepare more” – suggesting significant increases in defense budget, procurement, and troop size. The wake-up call had come a decade earlier, during the so-called “Russian Easter” in 2013 when Russian fighter jets simulated an attack on Swedish territory during a military exercise. The Russian aircraft had to be intercepted by Danish fighter jets on NATO’s Baltic Air Policing duty at the time, as all Swedish pilots were on Easter vacation. NATO later determined that it had been a simulated nuclear attack and Sweden concluded that national defense capability had not become entirely obsolete, after all.

However, NATO membership remained a question of political identity in Sweden. The narrative of 200 years of neutrality (or non-alignment after the Cold War) and staying outside of wars as a conflict party, instead emphasizing arms control and peacebuilding, has been an integral part of Sweden’s (and especially its Social Democratic Party’s) foreign policy tradition as a “moral superpower.” Finland’s preference to stay outside of the alliance, too, was to an extent a convenient excuse not to press the divisive issue, as Sweden joining NATO would have created “a strategically awkward situation” and could have brought back the Cold War-era “Finnish question.” But Russia’s full-scale invasion of Ukraine in February 2022 fundamentally changed the equation for Finland. Only a few days after the beginning of the invasion, public opinion in Finland shifted significantly in favor of joining NATO and set the political process in motion, initial Swedish resistance post-invasion notwithstanding. “Damned Finland, now we may also have to join,” was reportedly then-Foreign Minister Ann Linde’s reaction, when the government fully understood Finland’s intention. Suddenly, Finland was leading the way into NATO. After it became clear that Finland and Sweden would jointly submit applications for NATO membership, a headline in the tabloid Expressen thanked “big brother Finland” for “NATO-help” – in Finnish.

Military Drivers of Bilateral Cooperation

The statement that Finland’s NATO membership is incomplete without Sweden was not just political rhetoric but an assessment based on military logic. In terms of security of supply, Finland is somewhat of an island, given that it is surrounded by water in the south and west and only has a comparatively much shorter land border with Sweden and Norway in the north. The long land border with Russia is currently closed and likely will remain so for some time, which limits Finland’s supply lines to the western direction and underlines the island-like character. Therefore, the close cooperation with Sweden (and increasingly so with Norway in the north) is vital for Finland.

As Matti Pesu (2023) describes, “as a NATO ally, Sweden will primarily act as a staging area, facilitating onward-moving reinforcements for operations in Finland and the Baltic states. This role as a hub would also entail acquiring capabilities and functions that would directly and indirectly support the defense of frontline nations, particularly in the land theater of the European Arctic.”

The logistics connections and military cooperation between Finland and Sweden were major topics during President Stubb’s first state visit to Sweden, including the port of Gothenburg. Finland is extremely dependent on the Baltic Sea supply lines for both military and civilian-commercial purposes, and the port of Gothenburg is a key logistics node: It is the Nordic region’s largest port and main entry point from the Atlantic – both in peacetime as well as in crisis and war. Furthermore, Sweden’s navy, amphibious units, and air force play an important role also for Finland’s defense: “Sweden is strong on the water, under the water, and above the water,” President Stubb said.

FISE Cooperation: Friends with Many Benefits

Sweden’s central geographic location makes it important for military mobility and security of supply in the whole Nordic-Baltic region. Swedish territory connects the Norwegian Atlantic coast in the Arctic to Northern Finland and reaches all the way down to the Danish Straits in the southern Baltic Sea. Apart from the crucial sea lines in the south, the only land route connecting Finland to the western allies goes through Northern Sweden and to Norway’s Atlantic coast. Reinforcing the Arctic region in a crisis is essential in denying Russia the ability to cut off NATO allies from Scandinavia in the Greenland Iceland UK gap or along the Bear Island line. In addition to the centuries-long shared history and close contemporary relations, Finland therefore had a practical self-interest in having Sweden join NATO as soon as possible. Sweden gives Finland strategic depth, while Sweden, for its part, has always profited from having Finland between itself and Russia. Therefore, after Russia’s first invasion of Ukraine and annexation of Crimea in 2014, Finland and Sweden started expanding bilateral defense cooperation. In 2014, the governments of Sweden and Finland tasked their armed forces to enhance cooperation on both defense policy decisions and specific military areas.

A 2015 joint statement of the ministries of defense confirmed this commitment to deepened military cooperation. In 2018, a defense cooperation Memorandum of Understanding was signed, creating the conditions for joint operational and tactical planning, followed by a joint military strategic concept signed in 2019. In 2020, Sweden adopted a law that extended the powers to provide and receive operational military assistance within the Swedish-Finnish framework, and a bilateral host nation agreement was signed in 2022.

The operational results of these agreements have been manifold. But some of the so-called FISE cooperation formats precede the post-2014 agreements: Finland and Sweden have a long-standing cooperation framework between their navies with the Swedish-Finnish Amphibious Task Unit (SFATU), and, for example, the Amphibious regiment from Sweden and the Swedish-speaking Nyland brigade from Finland have been exercising together since 2001. The air forces have been exercising together on a near-weekly basis trilaterally with Norway within the Cross Border Training framework since 2009. The 2023 letter of intent of the Nordic air forces, including Denmark, added a key deterrence element into the Nordic-Baltic region: the combined Nordic fleet of about 250 fighter jets (Gripens in Sweden and soon F-35s in the other Nordic air forces) equals that of Britain and France. Dispersed basing of the Finnish F-35s in Swedish territory could become relevant in the future, as one challenge for the Finnish Air Force is its “restricted operating environment, within range of Russian cruise and ballistic missiles and relatively close to its advanced GBAD systems.”

It's the Geography, Stupid

Having Sweden as a full member of the alliance is a real game-changer. Sweden was the missing piece in the puzzle that has now changed the strategic outlook in the Nordic-Baltic region. The difference that it makes from NATO defense planners’ point of view is significant. What has always been a geographical reality now becomes executable: in 1950, a NATO military committee report stated that “Sweden, by reason of her economic, industrial and military strength, is a factor of considerable importance in any regional defense planning, but at present she is not a member of the North Atlantic Treaty. The full cooperation of Sweden, at some later date, would greatly enhance the defensive strength of the Northern European Region.” And, which is as valid today as it was in 1950: “Moreover, the Russians cannot ignore the possibility of Sweden joining the Northern Allies when Norway is attacked.” Therefore, NATO concluded already in its very early days that “the defense of the [Nordic] region must therefore be considered as a whole with the object of achieving one integrated and coordinated plan.”

Almost 75 years later, these considerations finally become a straightforward operational reality, with Sweden and Finland fully integrated into NATO’s new regional plans. Even if the assumption was, before becoming full members, that Finland and Sweden would fight on the side of NATO in a potential regional conflict, it was not possible to make official defense plans for and with the two Nordic countries. The NATO membership of Finland and Sweden fundamentally changes the geography of deterrence and defense in the Baltic Sea and Nordic region, even if it is not a silver bullet that solves the ‘Baltic dilemma,’ i.e., the challenging geographical position of Estonia, Latvia, and Lithuania caught between Russia and the Baltic Sea, with limited strategic depth for defense. However, Finland and Sweden shift the parameters of any potential battlefield with Russia and give NATO military planners new tools to defeat potential aggression in the Nordic-Baltic region.

Finland and Sweden bridge the geographic gap that disrupted NATO’s defense planning between the northernmost member Norway, along with Denmark, Germany, and Poland, to create a unified theater of operations from the Arctic to the North Atlantic, the Nordic region, and through the Baltic Sea. Now that their territories and military assets can be fully integrated into NATO’s defense and deterrence concept, planning and executing of NATO’s Baltic defense becomes much easier—and, even possible, in the first place. With Finland and Sweden in the alliance, NATO can now deliver on the 2022 Madrid summit pledge to “defend every inch of Allied territory at all times.” At the same time, the situation is now much more complicated for Russian planners.

The almost-joint accession of Finland and Sweden to the alliance has thus created one coherent geostrategic region running from the Arctic through the North Sea and Baltic Sea. Once a buffer for Sweden against Russian aggression, the Baltic Sea would become a regional security link. In times of crisis or war in the Baltics, Swedish air bases can readily receive NATO forces and send reinforcements. This is especially true for Gotland, which has served as a logistical hub often in the past millennium and will be an important puzzle piece for NATO’s defense plans for the Baltic States today. Integrated air and missile defense capabilities on this strategic island could reduce and even reverse the dangers to NATO from the Russian so-called anti-access/area denial (A2/AD) bubble around Kaliningrad and the Suwalki Gap. The geography also made the joint NATO application with Finland the only viable alternative for Sweden: in the middle of the Nordic-Baltic region, it could not realistically have stayed outside of NATO after Finland made the decision to apply. As Bergquist et. al. put it in their 2016 assessment of the effects of Finland’s potential NATO accession, “strategic decisions taken by one of the two countries have had immediate and decisive consequences for the other.”

NATO’s New Northern Flank: A Game-Changing Dilemma for Russia

Finland’s more than 1340 km long border with Russia has doubled the total length of the NATO-Russia border, which caused some alarm ahead of the accession of the newest member. But thanks to Finland’s notable defense capability, the longer border is an advantage for NATO, as it significantly complicates the outlook for Russian offensive campaigns. If attempting any attack on the Baltic states, Russia would first have to reinforce the border to Finland, which is currently exposed and blank of equipment and troops that have been drawn to Ukraine: Russia stripped even the air defenses around St. Petersburg in the early stages of the war. In the Northern Fleet base on Russia’s Arctic coast in the Kola Peninsula, the air and sea assets, including strategic nuclear submarines, are still widely intact. However, NATO could now hold these under threat, as the Russian base is located only around 200 km from the Finnish border.

Furthermore, the most significant change from NATO’s point of view is that the Baltic States can now be reinforced not only from air and land (from the south through Germany and Poland) but also from sea. A major headache for NATO planners used to be that the Baltic States were an exposed allied outpost, sandwiched between Russia and the Baltic Sea, and therefore relatively easy to cut off from the rest of the alliance, especially through the Suwalki Gap between Lithuania and Poland that connects the Russian exclave Kaliningrad to Belarus. Now, Finland’s territory has opened up a new supply route to Estonia, connecting it through Northern Sweden to Norway’s Atlantic coast—the only land route connecting Finland to the western allies. The Gulf of Finland is so narrow between Helsinki and Tallinn (only 80 km) that Russia’s Baltic Fleet is now stuck in the port of St. Petersburg, if NATO so decides.

For Latvia and Lithuania south of Estonia, the picture is somewhat more mixed: Sweden’s territory is a game-changer for NATO by connecting the whole region, from Norwegian High North down to the Danish Straits as an access point into the Baltic Sea in the south. Sweden has pledged to contribute a reduced brigade of up to 1000 troops to the multinational NATO Forward Land Force in Latvia. Sweden is assessed to even have the potential to take on a leadership role in the maritime domain in the Baltic Sea region, with its capable navy specialized in Baltic Sea shallow water and submarine warfare. However, Russia’s control over Belarus has mitigated the positive net effect of Sweden’s NATO membership for Latvia and Lithuania.

Sweden Has Always Mattered

Since NATO began working on its first defense plans in 1950, it has been clear that Sweden is key for the defense of Northern Europe. Sweden’s secret relations with NATO during the Cold War were so close that Americans jokingly called Sweden “neutral on our side.” With that background, it is not surprising that Prime Minister Ulf Kristersson said in his speech on the occasion of Sweden’s NATO accession: “With this membership, Sweden has come home.” The most important detail from a Finnish perspective is that as member of the same alliance, Sweden has now officially committed to defending Finland through a treaty obligation. NATO membership does not change but rather reinforces the fact that Sweden is Finland’s closest partner. This, as one key element in the wider context of Finland’s NATO membership, leads to the assessment in Finland that Finnish security has never been on a better foundation since gaining independence in 1917 – in a marked contrast to the Swedish assessment that Sweden’s security environment has never been worse since the Second World War.⁵⁷

As the Finnish journalist Sami Sillanpää notes in an essay, Finland and Sweden were finally reunited in NATO by the same power that separated them: Russia. In 1809, Sweden was deprived of what it had established in Finland already centuries earlier, and as Sillanpää points out, would be called “enhanced forward presence” in NATO-speak. As a result, both the Finnish and the Swedish assessment of the security situation are true at the same time: Although Russia’s war of aggression in Ukraine has shattered the post-Cold War European security order, it has had the side effect of jolting the Nordic countries even closer together. Finland and Sweden have never been closer, and therefore safer. And, as Sillanpää concludes: it is simply “kanonbra”.⁵⁸

Photo: Wikimedia commons