"Next time," Tsipras quipped, with a bit of an embarrassed grin.
Erdogan, like other senior Turkish politicians, is always seen in a formal suit and tie, a legacy of the Western-facing, secular principles of the Turkish republic's founder, Mustafa Kemal Atatürk. That doesn't mean everyone around him necessarily adopts the same habit.
But for Tsipras, his sartorial choice is an act of politics. Last year, the newly elected prime minister indicated that he would don a necktie only when Greece's debt problem was resolved. Greece's plight continues, and so Tsipras's neck remains free.
Most famously, Greece's then-finance minister, Yanis Varoufakis, stunned Europe's pious technocrats in Brussels and elsewhere last year when showing up to meetings in a leather jacket, sans tie, with his shirt often untucked.
The disregard for the tie is shared by other leftists.
"The tie is a useless rag that constrains your neck," former Uruguayan president José Mujica once told a Spanish TV station. "I’m an enemy of consumerism. Because of this hyperconsumerism, we’re forgetting about fundamental things and wasting human strength on frivolities that have little to do with human happiness."
Mujica is well known for his ascetic lifestyle and humble values, articulated perhaps most emphatically in this 2013 photo of him alongside the leading members of his government.
Away from Europe and the Americas, the tie has been interpreted by generations of politicians as a symbol of Western dominance and cultural imperialism. Leaders of a host of nations in Africa and Asia sport a whole range of local formal wear that has no need for the inhibiting cravat, which, if nothing else, is an oppressive accessory in tropical climes.
In 1955, the Bandung Conference held in Indonesia featured the major nations of the recently decolonized world. Luminaries such as Indian Prime Minister Jawaharlal Nehru and Chinese Premier Zhou Enlai exhibited their own closed-neck jackets, the former now commonly known as a "Nehru suit," and the latter, unsurprisingly, a "Mao suit."
The narrative of anti-imperial resistance surfaced once more after the 1979 Iranian revolution. The country's new clerical leaders banned the sale of the tie, considered a sign of Western decadence and even of the Christian cross. They're back on the shelves in Tehran, but Iran's political class eschews wearing them in any public setting.
Instead, while donning tailored Western suits, they wear a buttoned-up shirt with a banded collar that does away with any place for a potential necktie.
And, of course, there are times when politicians skip the tie for no ideological reason whatsoever.
See Japan in the mid-2000s, when then-Prime Minister Junichiro Koizumi ordered the nation's salarymen to leave their jackets and ties at home to reduce the need for air-conditioning during the scorching summer and conserve energy.
Or, perhaps most awkwardly, when leaders of the Group of Eight went "casual" for a photo-op that communicated little real bonhomie.
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