SERHAN TURKOGLU stands outside one of Istanbul’s many visa-application bureaus, clutching his flight and hotel bookings, travel insurance, proof of employment, social-security registration, recent salary slips and bank statements, and a vehicle licence. Mr Turkoglu, an accountant, needs all of this simply to secure a holiday visa to Spain. For his next European holiday he will have to go through the whole rigmarole again. “It makes you feel like a second-class citizen,” he says. Turkish diplomacy towards the European Union is focused on obtaining visa-free travel. It is easy to see why. Turkey has been negotiating to accede to the EU for more than a decade; it is the only candidate country whose citizens still need visas to enter the bloc’s Schengen area. Peruvians, Malaysians and Mexicans, by contrast, no longer need visas to travel there. Europe’s panic in the face of mass migration from the Middle East has provided Turkey with a new opening. In March, in exchange for a pledge to re-admit thousands of migrants deported from Greece, the EU offered Recep Tayyip Erdogan, the country’s president, €6 billion ($6.8 billion) in aid,...