ANKARA – When Nato invited Sweden and Finland into the military alliance in June, its leaders hailed a “historic decision” that showed their collective determination to face down Russian aggression in Ukraine. But the expansion plan has gone nowhere, with Turkey refusing to allow Sweden to join unless it does more to crack down on groups outlawed in Turkey, including the Kurdistan Workers’ Party, the PKK. As the dispute drags on, it is complicating efforts to present a united front against Moscow.

What does Turkey want?

It is demanding that Sweden extradite suspected Kurdish militants and alleged coup-plotters wanted by Turkey and stop supporters of Kurdish movements in Sweden displaying their allegiances openly. Turkey dropped its opposition to inviting Sweden and Finland into Nato after they agreed to cooperate with Ankara on countering terrorism, quickly address pending extradition requests and confirm that they would not block arms exports to Turkey. Days later, Turkey made clear that it would not ratify their membership if they did not fulfill those promises.

What happened next?

In December, Sweden’s Supreme Court ruled against the extradition of a man Turkey has accused of being involved in a 2016 coup attempt against President Recep Tayyip Erdogan. Turkey called the court’s decision “a very negative development”. In January, tensions flared anew after protesters in Stockholm displayed an upside-down effigy of Mr Erdogan. That was followed by the burning of a translated copy of the Quran near the Turkish embassy, which sparked outrage in Turkey and other Muslim nations. Mr Erdogan then announced that Turkey would not support Sweden joining Nato. Sweden has insisted it has done all it can to honour the June agreement, but Turkey says it has fallen short. Sweden’s laws on freedom of speech make it hard for the government to stifle public expressions of support for Kurdish independence.

What is Turkey’s problem with the Kurds? 

The Kurds are an Indo-European people, about 30 million strong, and one of the world’s largest ethnic groups without a state of their own. Their homeland is divided among Turkey, Syria, Iraq and Iran. The PKK has fought Turkish forces on and off since the mid-1980s as it seeks an autonomous region for Kurds inside Turkey. Turkey is particularly focused on the People’s Protection Units, or YPG, a Kurdish militia in Syria that was instrumental in the defeat of the Islamic State there. Turkey views the YPG as a security threat due to its ties to separatist Kurds in Turkey. 

Why is Sweden involved? 

Sweden has long sought to promote human rights and respect for minorities abroad, and the country’s welcome of refugees has made it home to as many as 100,000 Kurds. Some are Turkish opposition members sought by Mr Erdogan’s government. Sweden has tended to align with other European nations in the way it treats Kurdish demands for self-determination and was the first country after Turkey to designate the PKK as a terrorist organization, in 1984. Mr Erdogan has called Sweden a “nesting ground for terrorist organisations”. 

Why does the dispute matter?

Sweden and Finland conduct military exercises with Nato and increasingly share intelligence with it. However, they did not join the group earlier for historical reasons. Having Sweden and Finland in the alliance would arguably make it easier to stabilise the security of the area around the Baltic Sea and to defend Nato members Estonia, Latvia and Lithuania. Those countries are often seen as potential targets for Russian aggression. Including Finland and Sweden would add to Nato two sophisticated, well-equipped militaries whose gear is already compatible with that used by the alliance. It would double the length of Nato’s border with Russia, which now comprises just 6 per cent of Russia’s land perimeter, and enable the alliance to improve its surveillance of the country’s western flank.

What are the chances of a resolution?

It is hard to see a way out of the impasse for now. Mr Erdogan faces presidential and parliamentary elections in May and maintaining a tough stance against Sweden could consolidate his support in nationalist circles. The Nordic countries fulfill Nato’s criteria and their terrorism legislation and treatment of Kurds align with those of alliance members. The United States, the most powerful country in the alliance, has repeatedly urged Turkey to ratify their applications.

Where does this leave Finland? 

In a bind. Finland’s foreign minister opened the door to potentially decoupling its Nato application from that of Sweden following Mr Erdogan’s latest comments. But joining the alliance without Sweden would potentially risk Finland’s supply routes and Nato’s ability to provide security guarantees. It would also entail rolling back some military cooperation the two counties have developed over the years. They are close allies and had always insisted the process towards Nato accession would be coordinated. The official stance is still that they would enter Nato simultaneously. BLOOMBERG