German-Turkish relations are a high-stakes affair. Not only does Germany count some three million residents with roots in Turkey, the two countries are strategic to both the global economy and international diplomacy. In recent years, however, the relationship has been fraught with tension, and German Chancellor Angela Merkel recently declared her desire to “reinforce” bilateral relations with Turkey, as one state broadcaster reported last week.

Yet Merkel’s wishes run up against reality. One of the diplomatic spats to have erupted between the two countries started a year ago, when Deniz Yücel, a journalist for Die Welt, with German-Turkish dual-citizenship, was arrested in Istanbul over accusations of supporting “terrorism.” The news last Friday that the reporter had been finally released from prison has done little to shed light on that political and diplomatic mystery, and Yücel’s ordeal is indeed far from over, with prosecutors in Turkey still seeking up to 18 years of imprisonment.

There are also five other German citizens still stuck in Turkish cells on legally dubious charges. Perhaps the fact that six Turkish journalists were given life sentences on the same day as Yücel’s release is a sign from Ankara that it has no plans to change course. Indeed, Turkey holds the record for the numbers of journalists in jail.

The fact that a political leader in his own country needs police protection from a foreign delegation should be a wake-up call.

But a new sign of tension emerged this weekend, at the sidelines of the annual Munich Security Conference. Die Welt reported on Sunday that Cem Özdemir, the leader of Germany’s Green Party, had to be placed under police protection after the Turkish delegation, led by Turkish Prime Minister Binali Yildirim, complained to the police about his presence, referring to him as a “terrorist.” Özdemir, whose parents emigrated from Turkey and who was born in Germany, has been one of the most vocal critics of Erdogan.

Last week, Özdemir had urged Merkel to stop “cuddling” with Turkey. It is colorful language, to be sure. But the fact that a political leader in his own country needs police protection from a foreign delegation should be a wake-up call. This is all the more true at a time when tensions in the Mediterranean over oil and natural gas between Turkey and several smaller European Union countries are threatening to escalate. If the bloc’s smaller nations feel they don’t have the backing of the EU’s biggest economy, what will prevent them from turning their back on the idea of a united Europe?

No, what happens with Germany and Turkey is never about just Germany and Turkey.