For decades Turkey claimed the role of a bulwark on NATO’s southeastern flank. Today, it often behaves as a wedge inside the alliance. A Trojan horse that wields its veto, sows discord, and extracts concessions while cloaking itself in alliance legitimacy. Four episodes expose the pattern. A fifth, the facilitation of Russia’s sanctions evasion, seals the case.
Procurement of Russian S-400 missile system
In 2017, Turkey signed a deal to procure Russia’s S-400 air defense system, despite persistent warnings from NATO members that the system was incompatible with NATO’s security architecture. By 2019, deliveries began, sparking immediate fallout: the U.S. removed Turkey from the F-35 programme, fearing that S-400 radar data might compromise F-35 stealth capabilities. Washington imposed sanctions under CAATSA on Turkey’s defense procurement agency, the first time such measures were used against a NATO member on December 14, 2020. This was never just military procurement. It was a message: Turkey would assert strategic autonomy even at the cost of alliance trust.
Blocking Eagle Defender Plan
Turkey’s prolonged obstruction of NATO’s defense plan for Poland and the Baltic states, widely referred to as the Eagle Defender framework, offers a clear case study of such disruptive institutional behavior.
At a time when Eastern European allies were seeking formalized, rapid-response defensive planning in view of Russian assertiveness, NATO moved to operationalize updated regional defense structures. Political approval had been reached at leadership level. Yet implementation stalled for months because Turkey withheld final operational consent inside NATO’s military decision chain, as initially raised in NATO summit on December 3-4, 2019.
Turkey tied its approval of the Poland–Baltic defense plan to unrelated demands: that NATO allies formally classify certain Kurdish groups operating in Syria, particularly entities linked in Turkey’s view to the PKK, as terrorist organizations within NATO’s threat framework. In effect, a collective defense plan for Eastern Europe was used as a bargaining instrument for Turkey’s Syria-related security priorities.
The blockage persisted despite prior summit-level understandings and despite the urgency attached to Eastern flank defense planning. The result was institutional delay in activating contingency defense arrangements for frontline member states.
Eventually, Turkey lifted its objections after extended negotiation and pressure on June 30, 2020.
Blocking Finland’s entrance to NATO
Finland formally applied to join NATO in reaction to Russia’s invasion of Ukraine on May 18, 2022. Turkey immediately objected, alleging that Finland harbored PKK elements and demanding legal changes and arms-export guarantees. After nearly ten months of diplomatic pressure, Turkey’s parliament ratified Finland’s membership on March 30, 2023. Finland then joined NATO on April 4, 2023. A country on the front line of European security had to wait one year because Turkey chose to bargain.
Blocking Sweden’s entrance to NATO
Sweden applied alongside Finland on May 20, 2022. Turkey refused to ratify, accusing Sweden of providing safe haven to groups Turkey deems terrorist. Erdoğan offered conditional approval tied to Turkey’s demands at the Vilnius Summit, July 11-12, 2023. Finally, the Turkish parliament approved Sweden’s accession with a vote of 287–55 on January 23, 2024. Sweden became NATO’s 32nd member days later, 20 months after membership application. Sweden’s entry was not blocked by principle. It was bartered.
Facilitating Russian sanctions evasion
Even as NATO allies imposed unprecedented sanctions on Russia after the February 24, 2022 invasion of Ukraine, Turkey emerged as a critical conduit for sanctions evasion. Turkish exports to Russia surged by more than 100% in 2022, including dual-use goods such as machinery and electronics. The U.S. Treasury sanctioned Turkish firms for supplying components used in Russia’s defense sector in September 2022 and again in 2023. EU reports noted Turkey as one of the top hubs for rerouting sensitive goods, from microchips to industrial equipment, helping Russia blunt the impact of Western export controls. Rather than tightening the net, Turkey monetized the loophole: profiting from trade, facilitating Russian finance through its banking system, and expanding energy cooperation via the TurkStream pipeline. This is not ambiguity. It is active complicity that undermines NATO’s collective strategy against Russia.
The above episodes illustrate three deeper institutional risks.
First, it exposes the vulnerability of unanimity-based defense governance when a member state is willing to instrumentalize collective security mechanisms for unrelated geopolitical bargaining.
Second, it introduces uncertainty into NATO’s deterrence signaling. Defense plans are credible only when adversaries believe they can be activated without internal paralysis. Procedural hostage-taking weakens that signal.
Third, it shifts alliance behavior from rule-based coordination toward transactional bargaining, a transformation that disproportionately benefits actors willing to escalate institutional friction.
None of this implies that Turkey lacks legitimate security concerns. Every NATO member does. The problem is not the assertion of national interests. The problem is the method: conditioning unrelated collective defense measures on unilateral political demands undermines the functional logic of alliance solidarity. NATO can accommodate disagreement. It cannot function under recurring procedural coercion.
The above disputes should therefore be remembered not as a resolved technical episode, but as a warning: when alliance rules are repeatedly used as leverage tools, the alliance itself becomes the bargaining chip. And that is a strategic vulnerability. Not for one flank, but for all.
These are not random episodes. They form a clear pattern. Turkey uses its NATO membership not as a pledge of collective defense, but as a bargaining chip. The objections were not technical. It was not about force readiness, logistics, or strategic doctrine. It was political leverage.
It courts Russia militarily with S-400s, delays NATO enlargement for leverage, and enables Russia to evade sanctions designed to halt its war machine. A NATO ally that undermines NATO strategy. Not a pillar. A Trojan horse.