Ukrainian casualties are running at a rate of somewhere between 6oo and 1,000 a day. One presidential adviser, Oleksiy Arestovych, told the Guardian this week it was 150 killed and 800 wounded daily; another, Mykhaylo Podolyak, told the BBC that 100 to 200 Ukrainian troops a day were being killed. It represents an extraordinary loss of human life and capacity for the defenders, embroiled in a defence of the eastern city of Sievierodonetsk that this week turned into a losing battle. The sheer number – more than 20,000 casualties a month – raises questions about what state Ukraine’s army will...