At the recent NATO summit, Greek-Turkish tensions once again moved to center stage—this time in an informal but pointed exchange between Greek Prime Minister Kyriakos Mitsotakis and Turkish President Recep Tayyip Erdoğan.
F-35s and the Shadow of ‘Casus Belli’
Though the summit’s official agenda focused on boosting European allies’ defense spending, Greece and Turkey dominated sideline discussions—particularly over F-35 fighter jets and Ankara’s longstanding declaration of a casus belli against Athens.
The conversation centered on military balance in the Aegean, Turkey’s potential re-entry into the U.S.-led F-35 program, and the decades-old Turkish parliamentary resolution that declares war as a legitimate response to certain Greek actions in the region.
Erdogan: ‘Almost No One Knows What It Is’
Erdoğan claimed Turkey has never commented on Greece’s defense acquisitions—and urged Athens to reciprocate by refraining from public criticism of Turkish arms purchases. He also expressed cautious optimism about Turkey’s possible return to the F-35 program, noting ongoing talks with Washington—but stressed no final decision has been made.
When pressed on the casus belli, Erdoğan downplayed its relevance, saying most Turkish citizens are unaware of the term: “Casus belli is something almost nobody in my country knows. If you ask them what it means, they won’t know. So, in my view, there’s no reason to be preoccupied with it.”
Mitsotakis: ‘A Historic Orthographic Error’
Mitsotakis responded firmly. He clarified that Greece does not interfere in U.S. decisions on defense exports—but emphasized that major obstacles remain for Turkey’s F-35 reinstatement. Meanwhile, he reaffirmed Greece’s own modernization path: operational deployment of Rafale fighters, upgrading F-16s to the Viper standard, and integrating its first F-35s in the coming years.
On the casus belli, Mitsotakis called it a “historic orthographic error”—a phrase he used to underscore its incompatibility with NATO alliance norms and the spirit of neighborly cooperation both capitals claim to pursue. He recalled raising the issue directly with Erdoğan during a bilateral meeting months earlier.
“Two neighboring countries—even when they disagree—must learn to live peacefully and in good neighborliness,” Mitsotakis said. “In that context, the threat of war cannot be treated as normal. All of Europe understands that such a threat between allies contradicts the very essence of the Alliance.”
He noted the casus belli dates back to 1995 and argued it belongs in the past—not in today’s diplomatic or strategic calculus.