Turkish president Recep Tayyip Erdoğan has threatened an invasion of its neighbor and NATO partner Greece. The disputes between the two countries are numerous but lately have settled on the “militarization” of Greek Islands near the Turkish Aegean coast. Turkey claims that the military buildups in the islands are in reaction to Greek violations of the 1923 Treaty of Lausanne. Article 13 of the 100-year-old treaty states that “No naval base and no fortification will be established in the said islands.” However, the same Article 13 also states that “Turkish aircraft will forbid their military aircraft to fly over the said islands” and that “The Greek military forces in the said island will be limited to the normal contingent called up for military services.” 

Greece’s counterclaim is that Turkey has repeatedly violated its historical treaty obligations through continuous military flyovers and a consistent naval presence in the region. Greece has said that this threatens not only the territorial sovereignty of the islands but also the economic sovereignty of Greece’s continental shelf. While this source of friction brought the neighbors close to war in the 1970s, the two countries largely agreed to try to develop a framework for drilling rights and natural resource extraction in the eastern Aegean.

Over the past year, Turkey has applied increasing pressure on Greece and has adopted aggressive rhetoric. Erdoğan has threatened to strike Athens with ballistic missiles if it insists on “occupying” islands in the Aegean. At the 2023 World Economic Forum, Erdoğan warned the current Greek prime minister Kyriakos Mitsotakis that Türkiye “may come suddenly one night if they keep acting out” and that “[Mitsotakis] behave smartly or you will see the march of crazy Turks.” These bellicose statements follow other more ominous comments by Erdoğan: “We have only one word to tell Greece: Do not forget Izmir [Smyrna in Greek]” referring to the 1922 bloodletting that occurred when Turkish forces entered the Greek-occupied city of Smyrna. An estimated 100,000 people died in what Greeks have labeled as the “Catastrophe of Smyrna.” It is no surprise that such language alarms not only the Greek public, but also other NATO members.

It is difficult to assess whether Turkey will take the final plunge amid what will surely be a vitriolic reaction within NATO and elsewhere in the international community. But as Michael Rubin of the American Enterprise Institute has made clear, Erdoğan’s government could find it irresistible to use the recent flareup of the islands dispute as a pretext for an invasion. Looming elections potentially furnish Erdoğan with ample material to drum up nationalistic sentiment. Moreover, now that the Turkish courts appear to have prevented Istanbul mayor Ekrem İmamoğlu from running as a presidential candidate, Erdoğan may feel liberated from the constraints that may have heretofore stayed his hand.

Implications for NATO 

Another conflict between Turkey and Greece would confront NATO with difficult decisions. Turkey’s geopolitical significance cannot be overlooked. Beyond its control of the Black Sea straits, the Bosporus and the Dardanelles, it has historically been a platform from which to block Russian penetration of the Mediterranean and the Middle East, and from which America has been able to radiate its own influence. Over the last twenty years, Turkey simultaneously adopted a more populist and, given the pathologies of much of the Turkish public, anti-American approach. Since entering office, Erdoğan has empowered grassroots Islamism at the expense of the secular, pro-Western military elite. Similarly, Erdoğan’s adoption of Neo-Ottomanism and the Mavi Vatan sea strategy are at odds with American policy in the Eastern Mediterranean. Neo-Ottomanism attempts to build a coalition of nationalists and Islamists in Turkey, through the lens of Ottoman grandeur. In this way, a neo-Ottoman outlook offers both domestic groups something upon which they can agree. 

In contrast to souring relations between Washington and Ankara, the United States has vastly improved its relationship with Greece—the other half of NATO’s vital southern flank—since the election of Mitsotakis’ center-right government in 2019. This apparent shift in alliance relations multiplies the incentives for the United States to lean in Greece’s direction should hostilities occur, especially if Turkey is determined to be the aggressor. This appears to have shaped Erdoğan’s perception, with his blunt criticism of a new NATO base in Alexandroupoli, a Greek port sitting astride the Turkish border. This dynamic is further shaped by the diametrically-opposed trajectories of each ally’s domestic institutions, with Greece steadily liberalizing and Turkey moving in a more authoritarian direction. The Biden administration has positioned America to be one of the rallying democracies to oppose authoritarianism globally. A conflict between Turkey and Greece would provide this stance with a severe acid test. 

Geopolitical Impact 

The immediate implications of a Turkish invasion of the Greek islands are unclear. There are no provisions in the North Atlantic Treaty for sanctioning, expelling, or otherwise punishing a member state of NATO. In addition, NATO is constrained by procedure. NATO operates on the principle of unanimity is required, and unity amongst the twenty-nine member states requires compromise. For NATO to take any punitive action against one of its own would require the alliance to improvize its response to a Turkish invasion of the Greek islands. No real precedent exists. The closest analogy is the Turkish invasion of Cyprus in 1974. In this instance, NATO was helmed by leaders with clear priorities and strategic concepts which governed their actions—namely, holding NATO’s southern flank together and preventing Soviet penetration of the Eastern Mediterranean. Neither quality is present in NATO’s current leadership, as evidenced by the West’s essentially ad hoc reaction to the Russian invasion of Ukraine, in which no political objective has been set forth in spite of substantial efforts to tip the balance of forces in Ukraine’s direction. In the event of a conflict between two member states, NATO’s reaction is more likely to be paralysis than decisive action. 

The inherent ambiguity of the situation is unlikely to quell what will likely be intense international pressure to bring Turkey to heel, not only from within the alliance, but from the European Union as well. European leaders have maneuvered themselves into a position where they are bound to oppose aggression as a matter of principle irrespective of the context in which it occurs. 

Regardless of what NATO might do in reaction to a Turkish offensive, Ankara’s relationship with the alliance is bound to become more estranged, leaving Ankara with few good options. Turkey could potentially even leave the NATO alliance of its own volition, especially if Ankara finds American and European sanctions to be unbearable. Such an eventuality is unlikely, however, as there is no clear incentive for Turkey to make a demonstrative display of its departure from NATO, unless domestic politics demand it. Additionally, Turkey could withdraw from NATO’s command structure, similar to Charles de Gaulle’s symbolic display of defiance in the 1960s. The lack of any formal mechanism for the expulsion of a NATO member and the fact that “leaving” NATO’s command structure is more symbolic than tangible means that a more probable outcome would be Turkey retaining its official position while doing what it pleases, which is hardly a drastic change from its current posture. Turkey’s relationship with NATO is thus more likely to face slow erosion than a clean break. 

The most concerning implication of any diplomatic confrontation between NATO and Turkey is the threat of a deepening bilateral relationship between Ankara and Moscow effectively driving a wedge within NATO’s southern flank, essentially vitiating the purpose of Turkey’s presence in the alliance. Among the permutations such a new relationship could take is the increased sale of Russian weapons to Turkey, including the S-400 missile batteries that have been the source of so much consternation from Washington and Brussels. Ankara has slowly drifted toward Moscow under Erdoğan’s leadership, and the two countries already have close economic and investment ties. Hundreds of thousands of Russian citizens and businesses have invested in Turkey. Indeed, Antalya on Turkey’s southern coast is referred to as “Moscow on the Med.” Caleb Larson has previously covered the dangers posed by Moscow’s increasing presence in the Eastern Mediterranean. It is this that has the greatest geopolitical implications for the regional balance of power, and which American foreign policy in the region for the last seventy years has been designed to prevent. 

These trends are in part a reflection of Europe’s—and by extension NATO’s—receding coherence as a strategic entity, which the galvanizing impact of the war in Ukraine has partially obscured, but not absolved. Europe’s map is becoming more medieval in its complexion, with regions and subregions forming within NATO. Even the unifying effect of Russia’s invasion of Ukraine has proven somewhat conditional, as each member of the alliance appears to be moving at a different pace in rushing to the ramparts of European defense. Turkey, for its part, is beginning to reckon with its newfound geopolitical weight given the recent instability in the Middle East and Caucasus regions and is willing to exploit it at the expense of the alliance to an extent not seen in previous decades. The looming confrontation between Turkey and Greece drives home the need for NATO to regain its bearings and focus on fundamentals.