Whether or not Turkish leader Recep Tayyip Erdogan will ratify Sweden’s accession to Nato has become the focus of a high-level two-day summit the alliance is holding in Lithuania from Tuesday.
In the eyes of some western diplomats, the thorny issue overshadows an expected show of support for Ukraine’s Nato membership bid – though that is also proving controversial.
“It’s extremely important,” an adviser to French President Emmanuel Macron said.
“Deep down, everyone wants [Sweden’s] membership to happen as quickly as possible and hopes that the last obstacles will be removed without delay.”
Mr Erdogan is scheduled to meet Swedish Prime Minister Ulf Kristersson in Vilnius on Monday afternoon.
“A really good scenario would be if, in Vilnius, Erdogan says: I am satisfied with actions of the Swedish parliament and I am ready to put this in front of my Parliament,” a senior Nato diplomat said in a briefing to journalists.
“There are more than 50 per cent of chances that this happens, but let’s see.”
The final stage of approval in Turkey will be a parliamentary vote.
Meanwhile, all eyes are on Mr Erdogan as his diplomatic team continues to press allies for further concessions.
They may also include the possibility of purchasing F-16 fighter jets from the US after it kicked Turkey out of its F-35 programme for buying Russian missile defence systems in 2017.
Publicly, the biggest sticking point between Nato member Turkey and Sweden remains Mr Erdogan’s perception that Stockholm is not doing enough to push back against Kurdish militant groups operating on Swedish soil.
This includes blocking fund-raising operations run by the PKK, which is classified as a terrorist organisation both by the EU and Turkey.
Finland and Sweden filed a joint request to join Nato last May shortly after Russia’s invasion of Ukraine, in a break with their long history of neutrality and non-alignment.
Finland became a full member of the transatlantic alliance in April, but Turkey has continued to hinder Sweden’s accession.
Both Sweden and Nato’s Secretary General Jens Stoltenberg have repeatedly said that Sweden has done what was promised in an agreement signed last year with Turkey, including amending its antiterrorism legislation.
But Mr Erdogan has publicly raised other issues that are not mentioned in the memorandum, including public Quran burnings in Sweden. The Swedish government is considering whether to make it illegal to set the Quran or other holy books on fire.
Nato says it understands Turkish concerns about the PKK. The conviction last week by a Swedish court of a Kurdish man for attempting to finance the group was widely seen as a boost for Sweden’s Nato membership bid.
But many believe that Turkey wants to see more convictions and extraditions. This has put Swedish leaders in an awkward position as they cannot be perceived as interfering with an independent judiciary.
Turkey’s persistence has puzzled some western diplomats. “The Swedes cannot say 'we will deliver you person X, Y and Z,'” said the senior Nato diplomat.
An important mediator
Yet they are also aware that Turkey’s demands cannot be ignored. Since Russia’s invasion of Ukraine last year, Mr Erdogan has positioned himself as a mediator with strong links to both Ukraine and Russia.
Turkey is one of three Nato member countries in the strategic Black Sea region through which Ukrainian grain is exported under a UN and Turkey-brokered deal that is vital to the world’s food security.
“Securing Nato’s interests in the Black Sea depends on a strong Turkey,” wrote non-resident senior fellow at the Atlantic Council Rich Outzen and historian Pinar Dost in an article published by The Atlantic Council on Saturday.
“Ukraine understands this, leading its officials to consider Turkey as one of the few potential security guarantor countries."
In an apparent defiant move towards Russia, Mr Erdogan released five detained Ukrainian commanders during a visit to Turkey by Ukrainian President Volodymyr Zelenskyy.
The Kremlin accused Turkey of breaching an agreement that stipulated the men were supposed to remain in Turkey until the end of the war under the terms of a prisoner exchange.
Mr Erdogan also publicly endorsed Ukraine’s bid for a fast-track Nato membership, telling reporters “there is no doubt that Ukraine deserves” to join the alliance.
The move was described as “smart” by Sinan Ulgen, a senior fellow at Carnegie Europe. He said it demonstrated loyalty to Nato with “no costs attached”.
Many believe the US can play a role in softening Mr Erdogan’s stance on Sweden but the White House and Congress are at odds on a crucial aspect of US-Turkey relations – selling F-16s to Turkey.
US President Joe Biden responded favourably to Turkey’s request in October 2021 to purchase F-16s and modernisation kits but he has faced opposition from Congress.
Senior politicians want Mr Erdogan to become “less belligerent” and put an end to his opposition to Sweden joining Nato.
This gives Mr Biden little room to manoeuvre.
The next few days will given an indication of what kind of compromise can be reached.
"The Turks are very skilled negotiators," said the senior Nato diplomat. "Negotiations never stop until it's finally over."
