Putin must explain how his war allowed Russia to be invaded – and offering locals £90 each won’t do it | Sergey Radchenko

He maintains a tyrant's grip, but Ukraine's incursion into Kursk throws further doubt on his claims about the special operation'

On 6 August, a substantial Ukrainian force launched a cross-border incursion into Russia's Kursk region, shelling the little town of Sudzha and reportedly occupying several villages. Scores of Russian military were killed by artillery and drone strikes, while others were seen surrendering to the triumphant Ukrainians. It quickly became apparent that the incursion was on a far larger scale than previous border raids. Two and a half years into Putin's murderous invasion of Ukraine, Russia faced an unpleasant reality. It, too, could be invaded by a neighbour.

Ukraine's Kursk operation overlaps with a poignant anniversary. Twenty-five years ago, Vladimir Putin - previously the director of the Russian security service (FSB) and the secretary of Russia's security council - replaced the short-lived prime minister Sergei Stepashin.

Sergey Radchenko is Wilson E Schmidt distinguished professor at the Henry A Kissinger Center, Johns Hopkins School of Advanced International Studies in Baltimore