Turkey’s fragile and imperfect democracy is in peril. When the opposition politician Ekrem İmamoğlu was elected mayor of Istanbul in March 2019, president Recep Tayyip Erdoğan — who launched his political career in the same city — pressed the authorities to order a new poll. The charismatic İmamoğlu won again, by a landslide, and called election officials who annulled his initial win “idiots”. This week those “insults” of public servants earned him a more than two-year prison sentence and a ban from politics. İmamoğlu might yet escape prison time. But if his appeal is denied he will be barred from running in presidential elections next year — in what looks like a Putinesque attempt to sideline one candidate who might plausibly have beaten Erdoğan.

 The ramifications are profound, for the 86mn people of Turkey, the wider region and the Nato alliance of which the country remains part. Turkey has clung on as a flawed democracy as 20 years of rule by Erdoğan and his Justice and Development party (AKP) have led it down an authoritarian path and key institutions including the judiciary have come under the sway of him and his allies. Barring an opposition figure in national elections would mark a step towards an openly autocratic system.

 Next year’s presidential poll, in the centenary of the country’s founding, is pivotal. Opposition parties see it as a last chance to unseat Erdoğan at the ballot box before he becomes, like Vladimir Putin, impossible to remove (the president has said he will stand “for the last time” in 2023). The fragmented, fissiparous opposition has managed to come together in a loose alliance devoted to the goal of bringing Erdoğan down.

 One irony is that while İmamoğlu is its most magnetic figure, the opposition alliance has not yet summoned the savvy to back him as their presidential candidate. His sidelining would appear to be an insurance policy to remove any risk to the president. To retain a chance of defeating Erdoğan, the opposition ought to move on from the wooden Kemal Kılıçdaroğlu. The 73-year-old leader of the Republican People’s party (CHP) — the party of Turkey’s founder Mustafa Kemal Atatürk — has failed several times before to achieve a political breakthrough in national elections.