Donetsk is a Russian City

In the era of deep communism I had the mixed experience of visiting Donetsk with twin-city delegations from Sheffield. At the time of my second visit the local miners were paying a levy to support the suffering miners of South Yorkshire during the long Scargill Strike: money which, it transpired, never got into the pockets of the striking miners.
The delegation was taken down a major pit where conditions were worse than in any Victorian mine because modern machinery created levels of noise and risk that had not existed in the nineteenth century. The seam was only 80 centimetres high, so it could only be approached prone; and at 1.4 kilometres below the surface conditions of heat and dust added to the sense of terror that gripped most of us. That men who worked in these conditions were paying to support the well-fed strikers who enjoyed the cheap pints in Sheffield Union Bar when attending meetings in University premises seemed unjust.
Over the subsequent days I discovered that a mine fire would be quelled by pumping in inert gas: and it was accepted that any people who were trapped in the area of the fire would be gassed. A visit to the sanatorium to which miners with breathing difficulties caused by dust in the lungs were sent revealed caring but primitive treatment.
On neither visit did I hear any language used other the Russian and English. Whatever may have been the ethnicity of the city before it was virtually destroyed in the Second World War, its repopulation under Stalin was overwhelmingly Russian [including Russian-educated people from other areas of the USSR].

I was already familiar with the consequences of Woodrow Wilson's naive assertion of the 'principle of nationality' by which the former Habsburg lands were parcelled into Czechoslovakia, Romania and Yugoslavia; namely that each of those 'national states' included very significant minorities of other ethnic and linguistic groups. Some of these issues were resolved during and after Hitler's war: the Sudeten Germans [and other German minorities throughout Czechoslovakia and the newly-configured Poland] were expelled from lands where many of them had been settled since medieval times. Magyar [Hungarian] minorities were second-class subjects of Slovakia and Romania, and a strong residue of those groups remains in situ. So it is unsurprising that when Stalin set the frontiers of the Soviet Republic of Ukraine there was little concern for the linguistic and nationalistic sentiments of people near the boundaries; which leaves a few million Russians within the frontiers of the Ukraine.

During the Revolution that began in Kiev in 2013 some right-wing populists, both inside and outside the parliament, spoke of the forced assimilation or even the expulsion of Russian-speaking citizens. This caused anxiety among the Russian-speaking minority, which was captured by separatists who were quick to grasp at the [relatively few] 'fascist' speeches that could be deployed as threats to the ordinary Russian-speaking population. The recent  rhetoric of Ukrainian politicians, including the new President and successive Ambassadors in London, has demonised the separatists as 'terrorists' who must violently be suppressed. This has sanctioned the volunteering of individual Russians to support the 'rebels'; and masked the supply of arms and equipment from Russia.

 Slovakia and even Romania have learned to be accommodative to their minorities; Ukraine must do the same: quickly. Otherwise, the risk of war will unsettle Europe and the wider world.