When is an invasion not an invasion? The bitter experience of Ukraine suggests that if Russia sends a trickle of soldiers into its neighbour – rather than a flood – then it can somehow avoid the stigma of attacking another country. The Minsk ceasefire agreement of 12 February amounts to the latest attempt to end Ukraine’s long agony. People in the eastern city of Donetsk, now the de facto capital of a rebel state, say the accord has made some difference. “The situation has calmed down after the ceasefire announcement, however the shelling still takes place,” writes a friend who lives in the city. “It seems this in-limbo situation will never be tackled.”With eastern Ukraine suspended in limbo, this is a good moment to assess the state of the crisis