T his weekend it will be two years since the collapse of a shoddily constructed train station canopy in Serbia’s second city, Novi Sad. The tragedy , killing 16 people, was swiftly attributed to state corruption and failures of regulation, sparking student-led protests across the country.

Some of those demonstrators dared to imagine that they could become the catalyst for a democratic revolution.

On Sunday, that is more or less what happened. After sustaining their protests and turning them into a political movement, the students resoundingly defeated Aleksandar Vučić’s autocratic government in a snap legislative poll called by the president himself. Their victory constitutes one of the most remarkable election outcomes in recent European history.

For well over a decade Mr Vučić and his Serbian Progressive party (SNS) have exerted a domineering grip over civil society and the media, ruling through a combination of cronyism, patronage and bullying authoritarianism.…