On 21 May, Turkish President Recep Tayyip Erdogan notified NATO Secretary-General Jens Stoltenberg that Ankara would not support Sweden’s and Finland’s applications to join the alliance, thereby effectively obstructing the process as the accession of new members requires the approval of all NATO members.

While NATO insists on the importance of its open-door policy, officials in Ankara have stated that Finland’s and Sweden’s accession would be a “mistake” and Erdogan has indicated that he does not view their applications positively. His country does not want to repeat the same mistake it made when it agreed to readmit Greece into NATO in 1980, he said.

Ankara has made it clear that its approval for the Scandinavian countries’ bids would hinge on changes in their attitudes on issues of concern to Turkish national security interests.

The Turkish stance contrasts with the resounding support for the Swedish and Finnish applications from the Western countries. Stoltenberg, in a statement on 18 May, “warmly welcomed” the requests of NATO’s “closest partners” and stressed the alliance members’ determination “to work through all issues and reach rapid conclusions.”

French President Emmanuel Macron said his country “fully supports” Finland’s choice to join the alliance. Karen Donfried, US assistant secretary of state for European and Eurasian affairs, announced that Washington was ready to support Stockholm’s and Helsinki’s requests to join the pact.

Ankara’s solitary stance can only be understood in the context of its assessment of the implications of Sweden’s and Finland’s NATO accession for a broad array of concerns for Turkey, from various regional crises in which Ankara is a stakeholder to bilateral relations with Stockholm and Helsinki and its future interplay with the Western powers in the light of recent political developments and ongoing differences between Ankara and the Western capitals on a number of issues.

In addition, there is an undercurrent of tension between Ankara and NATO itself, which Turkey has frequently accused of failing to come to its support in the face of terrorist and border threats primarily from the direction of Syria. It has not forgotten how NATO refused to side with it during its collision with Moscow following the downing of a Russian jet over Syria near the border with Turkey in 2015.

Ankara’s close relations with Moscow also create certain constraints on Turkey’s options. In the spirit of that partnership, Turkey has always opposed NATO enlargement up to Russia’s borders, and its opposition to the accession of Sweden and, above all, Finland, is consistent with this.

Ankara and Moscow are bound by strong economic and military ties. The S-400 missile defence system that Turkey recently purchased from Russia is an example of the latter. In addition to collaboration on many joint commercial and investment projects, the two countries are also collaborating on major energy projects that might be considered a keystone of their bilateral relations.

Turkey is worried by the spectre of military escalation in the event of the Scandinavian countries’ accession to NATO. Moscow has repeatedly cautioned those two countries against taking this step and warned that it would take “military and technical” countermeasures. Ankara believes that further NATO enlargement in that direction courts a direct confrontation between the alliance and Russia, the repercussions of which would inevitably be felt in Turkey.

On 20 May, Russian Defence Minister Sergei Shoigu said in televised remarks that his country would establish 12 new military units and divisions in its Western Military District by the end of the year in response to NATO’s anticipated expansion to Finland and Sweden and what Shoigu described as “the increased threat to Russia’s borders” due to increased NATO military deployments.

Undoubtedly, Turkey fears that the inclusion of Sweden and Finland in NATO will affect its own expansionist calculations, not least in the Caucasus and Eastern Europe. While technically neutral up to now, Stockholm and Helsinki have been frequent critics of Turkish policy. In October 2021, they lashed out at Ankara for expelling the ambassadors of 12 European countries in response to their calls for the release of the Turkish rights activist and opposition figure Osman Kavala.

Turkish thinking must be that if Stockholm and Helsinki had been so outspoken before they joined NATO, imagine how antagonistic they would be once they are inside the alliance. Ankara will recall the Greek precedent in this context and the price it had to pay for its “mistake” in approving Greece’s readmission, the most recent example of which, to Ankara’s mind, has been Athens’ campaign to mobilise the NATO nations against Turkish energy exploration in the Eastern Mediterranean.

Not only does Turkey not see Sweden and Finland as potential allies or friends, it sees them as the “hosts of terrorist organisations”. Ankara has frequently accused Stockholm and Helsinki of “sheltering terrorists,” by which it refers to members of the Kurdistan Workers Party (KKP) and the Gülen Hizmet Movement. The Scandinavian countries’ support for the KKP and Hizmet, which Erdogan blames for masterminding the failed coup in Turkey in the summer of 2016, infuriates Ankara.

In the light of this, it is little wonder that Turkey has greeted the NATO membership requests of the two countries so coolly. The thought that opponents of the Turkish regime are free to operate in Finland and Sweden will only strengthen Ankara’s resolve to oppose their applications.

“Turkey’s position on Sweden and Finland’s membership of NATO is very clear and understandable,” said Efkan Ala, deputy chairman of the ruling Turkish Justice and Development Party (AKP). “These countries should very clearly reconsider their relationship with the terrorist elements of the PKK and put an end to it.”

Noting that a Swedish minister had recently attended an activity that he alleged was organised by the PKK, Ala added that “the problem of terrorism is not understood by these countries the way Turkey wants. They do not give it sufficient importance,” even as Turkey is expected to respond to their security problems.

The Finnish and Swedish NATO membership requests put Ankara in an excellent position to leverage its approval, essential if they are to be admitted, in order to settle a number of bones of contention with other Western powers in its favour. Among the problems that most nettle Turkey are US support for the Kurds in Syria and Washington’s responses to the Turkish purchase of the S-400 missile system, such as its decision to suspend Turkey’s participation in the F-35 Stealth Jet programme and its refusal to approve the sale of F-16 fighter jets to Turkey.

Already there are signs that Washington is softening its positions on these issues, which a US State Department memo has argued would be “in line with US national security interests and would also serve NATO’s long-term unity.”

Another area where Turkey might wield its leverage is in the context of oil and gas exploration and maritime boundaries in the Eastern Mediterranean. If it remains unable to rally support for its territorial claims, at least it might temper European support for Greece.

Given such dynamics, it is likely that the Turkish resistance to the Swedish and Finnish membership of NATO will last for some time. There are now two possible scenarios. One is that Ankara will dig in its heels in the light of Sweden’s and Finland’s continued “sheltering” of the AKP’s political opponents and their alleged lack of respect for Turkey’s security concerns. The other is that Ankara will begin to soften its position in exchange for progress during talks on some of the above-mentioned concerns.

At the moment, the latter scenario seems the more likely in view of the “positive” meeting between the Turkish foreign minister and his Swedish and Finnish counterparts on the sidelines of the NATO meeting in Berlin on 14 May. Afterwards, Turkish Presidential Spokesman and Senior Adviser to Erdogan on foreign affairs Ibrahim Kalin told Reuters that “we are not closing the door. But we are basically raising this issue as a matter of national security for Turkey.”

At the same time, Ankara is aware that a possible price for its resistance to the Nordic countries’ NATO bids is an increasingly strident media campaign against it, casting it as “pro-Russian” and causing a resurgence of tensions in Turkey’s foreign relations that Ankara has been working to reduce.

It may further fear that Western nations such as the US, the UK, France and Germany will combine forces to escalate this campaign and impose sanctions on Turkey for its refusal to conform to their wishes. Any punitive measures would further rock the already shaky Turkish economy at a time when the country is looking ahead to crucial presidential and legislative elections a year from now.

In sum, Ankara has many factors to weigh, and its calculations could fluctuate considerably in the light of the reactions of the Western powers and other developments in the weeks and perhaps months to come.