Economic sanctions were meant to be the West’s secret weapon against Russia, a way of crippling Vladimir Putin’s war machine and bringing his invasion of Ukraine to a halt without Nato firing a shot. Instead, Russia’s economy and military remain in rude health. After recent heavy attacks north of Kharkiv, Putin’s troops have seized more than 38 square miles of territory and stretched Kyiv’s already thinly deployed defences as they grind forward in Donbas.