A s polling stations closed across Serbia on Sunday evening, riot police were deploying around the presidency in Belgrade. Many of us feared the worst: massive electoral fraud, a refusal to recognise defeat or outright violence. After nearly 15 years of Aleksandar Vučić’s increasingly authoritarian rule, a peaceful transfer of power seemed implausible.

I had good reason to feel afraid. I am co-founder of an annual conference on the security and foreign policy challenges shaping the western Balkans, and sit on the international advisory committee of a civil society thinktank, the Belgrade Centre for Security Policy . Such work would be uncontroversial in most countries seeking European Union membership. Under Vučić’s regime, it was anything but.

Over the past two years, our organisation has faced cyber-attacks by actors suspected of links to Russian intelligence, spyware attempts and relentless vilification by pro-regime media.…