Turkish Foreign Minister Mevlut Cavusoglu is set to meet his U.S. counterpart Antony Blinken in Washington this week. There are scant expectations among observers that the visit will resolve any of the outstanding issues in what has been an increasingly troubled bilateral relationship, with the Biden administration keeping its distance from Ankara over allegations of human rights abuses and the Eurasian country’s increasingly warm ties with Moscow.

Turkey has reaffirmed its uncompromising stance on the fraught NATO bids of Sweden and Finland, setting the stage for a showdown with serious long-term implications for both Ankara and the alliance.

Ibrahim Kalin, a spokesman for Turkish President Recep Tayyip Erdogan, said on Saturday that Ankara is “not in a position” to approve Sweden’s NATO bid until all of Turkey’s concerns have been addressed. “We have a time issue if they want to join NATO before the NATO summit in June,” he added, noting that Sweden’s judicial system must change its legal definition of terrorism for Turkey to lift its opposition to Stockholm’s accession, which requires the unanimous approval of all member states.

Stockholm and Helsinki simultaneously submitted applications to join the alliance in May 2022, citing the new security realities brought on by Russia’s February 24 invasion of Ukraine. Their accession process, which NATO Secretary General Jens Stoltenberg assured last summer will be the fastest in the alliance’s history, has been delayed indefinitely amid unresolved Turkish objections.

Ankara officials said the two Nordic countries have continued to shelter Kurdish militants, with President Erdogan insisting their accession bids cannot move forward until they agree to extradite persons sought by Turkish authorities on terrorism charges. Yet Swedish and Finnish courts have denied several extradition requests, including one reportedly pertaining to exiled dissident journalist Bulent Kenes. Cavusoglu decried the rejection as a “very negative” development, insisting that the two Nordic countries have not taken sufficient steps to satisfy Turkey’s strict conditions for clearing its objection to their accession. “We no longer want to hear good words from Sweden and Finland, we want to see concrete steps,” Cavusoglu said.

Swedish Prime Minister Ulf Kristersson said early in the new year that his country has done all it could to address Ankara’s concerns even as Turkish officials continue to insist Stockholm has not done nearly enough. Tensions over Sweden’s NATO bid reached a fevered pitch after footage emerged last week of an Erdogan effigy hanging from a lamppost in Stockholm, prompting a furious response from Turkish officials. “Unless the activities of terrorist organizations are halted, it is not possible for the NATO membership process to progress,” said Kalin, according to Al Jazeera.

The Nordic applicants appear no closer to sealing an accession deal with Turkey today than they were over half a year ago when talks began. Turkish experts contend Ankara is unlikely to drop its opposition to NATO enlargement until after the June election cycle in Turkey, with Erdogan facing a stiff re-election challenge against a six-party opposition coalition. Others have suggested Turkey’s extradition demands from the two applicants are a facade for larger concessions it is seeking to extract from the United States — namely, a $20 billion sale of F-16 fighter jets. Though the Biden administration has signaled it intends to greenlight the deal, at least one top senate Democrat — Bob Menendez, chairman of the Senate Foreign Relations Committee — has already vowed to block it.

It is generally consistent with Erdogan’s modus operandi to levy ambitious demands vis-a-vis his interlocutors only to settle for a more modest set of concessions when all is said and done. Yet there is also a clear precedent for the Turkish leader doubling down in response to international pressure. Erdogan proceeded in 2018 with plans to purchase the Russian S-400 missile system despite U.S. warnings that there will be significant consequences and refused to reverse his decision even in the face of CAATSA sanctions and Turkey’s costly removal from the F-35 partner program.

The current impasse over NATO enlargement could play out in several ways over the coming months. Anxious to bring the matter to a close, Washington and its allies may become progressively more heavy-handed in pressuring Ankara to back down through public and private channels. Erdogan, who is well-known for his eristic tendencies even in dealing with leaders of allied nations, may very well respond by lashing out in unpredictable ways.

Though it remains unlikely that a confrontation along these lines would lead to Turkey leaving or being expelled from NATO, it would shake the unity of the alliance at a dangerous moment for European security. Further still, an aggrieved Erdogan bent on undermining the organization from within could prove just as corrosive to NATO in the long run as a formal divorce between Turkey and the alliance.

Then there is the not-insignificant possibility — one that appears to have grown more likely in recent weeks and months — that Turkey could end up torpedoing the NATO bids of Finland and Sweden altogether, leaving the applicants and the alliance in uncharted waters. But regardless of how the accession drama plays out, the standoff has exposed what has become a foundational challenge for NATO in the post-Cold War world: the principle of limitless horizontal expansion has heightened the risk of internal contradictions among NATO’s increasingly diverse membership, making it more difficult over time to distill common geopolitical goals and to maintain the credibility of the Article V commitment that is at the heart of the alliance.

This dynamic poses a serious and growing liability for an organization that must make every major decision on a consensus basis.

Turkey’s actions in holding up NATO enlargement come as part of Erdogan’s larger effort to chart what he sees as an independent foreign policy course between Russia and the West. Ankara rejected the maximum pressure strategy against the Kremlin adopted by NATO’s leadership and most member states in response to Russia’s invasion, instead positioning itself as a neutral broker between Moscow and Kyiv.

Ankara’s neutrality has yielded some success in the form of the Black Sea Grain Initiative, the only significant international treaty involving both Russia and Ukraine since the war’s outbreak. Erdogan has been able to carve out this niche in a unique wartime context: none of the major Western powers have been willing to engage Russia in direct talks, giving outside players opportunities to fill the void.

The conflict poses something of a paradox for Ankara. Erdogan is committed to facilitating a negotiated end to the war and came much closer than anyone else to doing so, according to reports from the failed Antalya summit in March. Yet it is precisely the war that has empowered Turkey with a degree of international clout that would otherwise have been unattainable. It remains to be seen to what extent Erdogan’s successor — regardless of whether they enter office as a result of this year’s election or at a later point — will seek to carry on his ambitious vision, nor is it clear how exactly the inevitable transition to a post-Ukraine War landscape will alter the strategic imperatives confronting Turkey.

The war has been a catalyst for geopolitical change, prompting both NATO and Turkey to pursue policies unthinkable in peacetime. The story of these transformations, closely tied as they are to the war’s course and its eventual outcome, is still being written.