So is Turkey finally going to let Sweden into NATO?

Turkish President Recep Tayyip Erdoğan is pretty much the most popular guy in town these days — if that town is Vilnius, Lithuania, and if you’re popular because everyone has to be nice to you so you’ll let a really good friend join your military alliance.

Sweden, by the way, is that really good friend. And ahead of the North Atlantic Treaty Alliance (NATO)’s big summit next week, the Turkish leader has so far refused to drop his objections to Sweden joining NATO, potentially sidelining Stockholm’s membership indefinitely and spoiling NATO’s sought-after moment of unity and cohesion in Vilnius.

All NATO members must approve new ones, so Erdoğan’s opposition is effectively a veto. The Turkish president is not alone; Hungary’s Viktor Orbán is also holding out, but Hungary has signaled it won’t be the final roadblock. Erdoğan has continued to insist that Sweden has not done enough to crack down on people in Sweden with ties to Kurdish militants and other groups that Turkey has deemed terrorists.

Sweden has tried to appease Turkey, including passing a new anti-terrorism law that went into effect June 1. But Erdoğan’s definition of terrorists is pretty expansive, and often includes dissidents and others critical of his regime. And even if Turkey has a case, Sweden has to follow due process and rule of law and can’t just, say, extradite a bunch of people on a whim. A recent Koran-burning outside a Stockholm mosque has added to tensions, as Turkey interprets these as Sweden’s permissive attitude toward anti-Islamic protests rather than freedom of speech.

Sweden, alongside NATO allies, has been doing some furious diplomacy to try to persuade Turkey to approve Sweden’s bid. Swedish and Turkish officials talked Thursday, with NATO Secretary-General Jens Stoltenberg saying they made “good progress” but issues remained unresolved. Stoltenberg will meet Monday with Swedish Prime Minister Ulf Kristersson and Erdoğan, a day before the Vilnius summit kicks off.

Until then, the impasse prevails. Which means the thing everyone really wanted to happen — that Sweden would join NATO, becoming its 32nd member — might not happen this week in Lithuania. This will deny NATO its unity narrative in Vilnius, something the alliance very much wants to project.

But it is more than just the storyline: Sweden is cooperating and planning closely with NATO, but it remains outside the alliance, and its mutual defense protections. If Erdoğan won’t budge here, after everyone shuttling to meet with Turkish officials, after Swedish concessions, and during the military alliance equivalent of the Super Bowl, it’s not clear when he would — which could leave Sweden stuck outside the alliance at time when NATO is trying to redefine and reinvigorate itself amid Russia’s ongoing invasion of Ukraine.

Erdoğan’s gonna Erdoğan. But that has real implications for NATO.

It wasn’t supposed to be this way. Last summer, in the wake of Russia’s invasion of Ukraine, Finland and Sweden dropped their long-held stance of nonalignment and announced their intention to join NATO. The two European Union countries had a long history of cooperating closely with the alliance, and both are strong, stable democracies — typically the ideal formula for a smooth membership.

Erdoğan saw it differently. The Turkish leader opposed their bids because of what he saw as the countries’ support for Kurdish groups that he regards as terrorist organizations, and because of the countries’ arms embargoes on Turkey. At last year’s NATO summit in Madrid, Turkey, Finland, and Sweden all agreed to a memorandum of understanding that seemed to resolve these issues.

But it didn’t last. Though the Turkish leader ultimately allowed Finland to join (which it did in April), he continued to block Sweden’s entry, saying that it still had not been tough enough on terrorists.

The hope was that Erdoğan, fresh off a big reelection win this May, would no longer be seeking easy political wins, and so might ease off his Sweden stance by the time this summit rolled around. But just because Erdoğan won another term didn’t mean he would become a different president. As experts said, he would see the election as a way to reset relations with the West — but on his terms. Which meant few Turkish observers thought he’d rush to ratify Sweden’s NATO membership after the election, at least not without getting something in return.

That something might be F-16 fighter jets. The Biden administration has been very clear that it will be happy to let Turkey buy upgraded equipment, and hasn’t even been all that discreet about using it as leverage in this effort to get Sweden into NATO. “I congratulated Erdogan. He still wants to work on something on the F-16s. I told him we wanted a deal with Sweden, so let’s get that done,” Biden said after Erdogan’s election win in May.

But it isn’t quite that simple. Congress ultimately has a say over weapons transfers, and it has continued to object to an F-16 deal over the Sweden-NATO standoff, but also other concerns, such as Turkey’s anti-democratic slide and Syria. Turkey has bristled at the idea of a possible quid pro quo, basically saying that, as a NATO ally, it needs those F-16s for its security, and the security of the alliance, which is separate from the Sweden issue.

Taken together, it’s not completely clear what is going to convince Erdoğan. Sweden has made concessions, including strengthening its antiterrorism laws and by agreeing to extradite some individuals, including an at least one person convicted of a drug crime in Turkey in 2013. (The person claims the real reason for his extradition are his PKK ties.) But Sweden is also trying to walk a delicate line, as both its government and its citizens have insisted they will not compromise on rule of law to appease Turkey.

Erdoğan, who has eroded those institutions and principles in Turkey, may not necessarily see Sweden’s perspective, and he and his officials keep insisting they want to see more action against terrorists. “The essence of the alliance is the institution of mutual trust and solidarity. Without it, it’s meaningless to talk about other subjects,” Erdogan said in a speech on Friday, according to Al-Monitor.

Of course, lots of NATO allies would probably say the same to Turkey: where’s the trust and solidarity, especially when we need it most? Officials and experts seem more measured in their optimism ahead of Vilnius, hoping Turkey changes its mind but recognizing it might not. Even if Erdoğan drops his objections — and Orban follows suit — their respective parliaments still have to ratify membership, so Stockholm will still have to wait a bit longer to formally ascend into the alliance.

Few NATO members want to deal with Turkey’s obstruction right now. Officials in NATO governments see Sweden’s membership as a priority, but the pact has a lot of other pressing stuff on their agenda as they meet in Vilnius. Countries will make commitments to defense spending, something the alliance has long sought, but has struggled to achieve.

There is the also the fraught issue of security guarantees for Ukraine, as Kyiv seeks more tangible assurances on future NATO membership. Alliance members are split on how concrete they want to be with Ukraine, showing support for its eventual membership, but without overpromising with Kyiv engaged in a war with an unclear outcome. A lot of these debates will happen behind the scenes, and while a little will spill out into the public, it won’t be as public as this Turkey-Sweden-NATO drama.

Which is why there is an urgency in resolving this Sweden standoff. The longer the feud drags on, the greater the reputational damage it does to an alliance that seeks to reinvest in its defense and also evaluate its purpose and and mission, in Europe, but also beyond. It is a little boost for Putin, whose aggression in Ukraine spurred this Nordic NATO expansion, but who is stands to gain from Turkey’s obstructionism. Putin always seeks to exploit alliance divisions for his political gain — and he could probably use that right about now.

Sweden’s membership would be a security boon to the alliance; all the Nordic countries would be in the mix, and that will reshape planning and security in the Nordic, Arctic, and Baltic regions. And the worst time for any wanna-be NATO member is when its declared its intention to join, but isn’t yet a member. Sweden can cooperate all it wants, but it isn’t covered by the mutual defense protections. While the threat is probably not super urgent, it’s still an uncomfortable position for Stockholm to be in, especially since the initial plan was for Finland and Sweden to do this together.

NATO really, really does not want this to drag out any longer, for fear this turns into a North Macedonia situation. But right now, it’s just not clear what exactly will get Erdoğan to let Sweden sit at the cool kids’ military-alliance table.