On the afternoon of 18 February 1952, the Turkish Grand National Assembly met in a hurry. Foreign Minister Fuat Köprülü told the chamber that the Atlantic Council would convene in Lisbon that Wednesday and asked deputies to move the accession bill ahead of everything else on the agenda. The record notes the applause. When the vote came, the bill making the Republic of Türkiye a member of the North Atlantic Treaty passed 409 to nothing, with a single abstention, and the assembly rose for a two-minute silence for its dead in Korea.

That silence is the whole story in miniature. The order is the point: Türkiye earned its seat before it took it, in a war fought a continent away.

First the dying, then the seat

Türkiye bled its way into the alliance. The Turkish Brigade shipped to Korea in October 1950, more than a year before the accession vote, while the country was still an applicant the alliance's northern members were reluctant to let in. It was sent to be seen. That winter it was seen at Kunuri, where it held and counterattacked to cover a retreat that could have become a rout, and lost close to a fifth of its strength doing it. By the armistice Türkiye counted 721 killed and more than 2,000 wounded, the third-heaviest toll of any of the nations that sent troops, after the United States and Britain.

And Türkiye was not alone in the arithmetic. On 18 February 1952 the alliance admitted its first two new members on the same afternoon, and both had already paid for the seat. Greece had sent its own battalion, the Spartans, who reached Busan in December 1950 and left 196 dead in Korea. Two countries on NATO's southeastern edge joined the same day, and both had written the down payment in casualty lists before a vote was cast.

In the Ankara chamber, the deputy Rıfkı Salim Burçak said it without varnish, crediting "the Korea decision and the honorable service of our heroic army" for the fact that Türkiye was joining "with equal rights and equal duties." Government and opposition agreed; the CHP called the pact a national achievement.

The ally Washington could not lose, or trust

The membership was never placid. After Türkiye's 1974 Peace Operation in Cyprus, undertaken as a guarantor power under the 1960 treaties to protect the Turkish Cypriots, the US Congress imposed an arms embargo that ran from 1975 to 1978 and pushed Ankara to build its own defense industry. What Washington thought of its ally in those years is now on the record. A 2025 study of the declassified files by the historian Macide Başlamışlı shows that a 1975 National Security Council memorandum, NSSM 227, recast Türkiye from a "special ally" into an "unreliable yet indispensable" partner: the trust damaged, but the geography and the bases too valuable to lose. A parallel CIA assessment warned that if the embargo held, it could weaken deterrence on NATO's southern flank and shake the whole structure of the alliance's collective defense. Ankara drew its own conclusion and set about no longer depending on weapons that others could switch off.

Cut out again, fifty years on

The lesson kept its shape and changed its form. Türkiye was one of the F-35's partner nations, a builder of the stealth fighter as much as a buyer of it, with Turkish firms making more than 900 of the jet's parts, several of them as the program's sole source. Ankara had ordered roughly 100 of the aircraft and paid some 1.4 billion dollars into the program, and six jets built for it were already in the United States, with Turkish pilots training on them. Then in 2019, after Ankara took delivery of the Russian S-400 air-defense system, Washington expelled Türkiye from the program, moved its parts to other suppliers, and sanctioned its defense-procurement agency. The six aircraft never left American soil: they went into storage, and the US Air Force bought them for itself. The 1.4 billion dollars was never refunded. Ankara has pressed ever since for the jets it paid for or its money back, and has recovered neither.

Ankara answered as it had in the 1970s, by building its own. Turkish Aerospace flew the KAAN, a twin-engine fifth-generation fighter of domestic design, for the first time in February 2024, with a home-built engine in development to replace the American ones in its prototypes. The air force has ordered its first squadron, and Indonesia has signed on for dozens more. The F-35 doors closed, and a Turkish assembly line opened.

The hand on the straits

Some of what Türkiye brings the alliance is simply where it sits. Under the Montreux Convention of 1936 it controls the Bosphorus and the Dardanelles, the only sea gates between the Black Sea and the Mediterranean. When Russia invaded Ukraine in 2022, Ankara recognized the fighting as a war and invoked the convention's Article 19, closing the straits to the warships of both belligerents alike, save those returning to their home ports. In practice that shut the door on reinforcing the Russian Black Sea Fleet from outside, an advantage NATO gained through a treaty a Turkish government has guarded for 90 years.

The bombs, and the second army

At İncirlik, in the south, the alliance keeps part of its nuclear deterrent on Turkish soil. The base hosts American B61 tactical bombs under NATO's nuclear-sharing arrangement, an estimated 20 to 50 of them by the reckoning of arms-control researchers such as the Federation of American Scientists, though Washington holds the arming codes and Türkiye, a party to the Non-Proliferation Treaty, keeps no nuclear weapons of its own. Set beside that the second-largest military in the alliance after the United States, and NATO's Allied Land Command, which runs the pact's land forces from İzmir, and the shape of the contribution is clear.

Indispensable, never easy

Seventy-four years on, the phrase from that 1975 memorandum still fits. Türkiye is the member the alliance cannot do without and cannot fully predict, a guarantor of the southern flank that also drives its own bargains, most sharply in 2003, when its parliament refused to let American troops invade Iraq from the north. The seat it took in 1952 was paid for in Korea, and it has spent the decades since making the alliance need it. Geography saw to the rest.