With the Russian military performing poorly, Ukraine is clarifying strategy and pushing back with modest successRussia’s invasion of Ukraine, now entering its fifth grim year, has already gone on longer than the entire fight on the eastern front in the second world war. The Soviets marched from the gates of Leningrad to Berlin in a little over 15 months in 1944-45; today the Russian rate of gain in Pokrovsk in Ukraine is 70 metres a day, in Kupiansk, 23 metres, according to the Centre for Strate...