The situation in eastern Ukraine remains murky; the optimism that developed a week and a half ago after conciliatory remarks from Russian President Vladimir Putin now seems to have dissipated. According to the BBC, Ivan Simonovic, the United Nations assistant secretary general for human rights, said that things were approaching a “point of no return” and that there were “worrying echoes of the 1990s war in his native Croatia”.

On Friday it was reported that steelworkers had joined with pro-government forces in Mariupol (on the coast of Luhansk province) to retake control from separatists. It’s an odd echo of the old left-wing demand of “arms to the workers”, with its implicit threat of full-scale civil war.

Putin no longer looks in control of the situation, if indeed he ever was. While I’ve no doubt that the unrest in the east was primarily Russian-inspired, that doesn’t mean Moscow can now do what it likes with it. Nationalist agitation is easier to turn on than to turn off.

That makes it important to understand something of how nationalist sentiment works in Ukraine. The essential ingredients are the 2001 Ukrainian census figures and the 2010 presidential election results, which correlate remarkably well. I’ve tried to summarise them with the aid of this map of Ukraine’s provinces (base map courtesy of Wikipedia …

The pink area is where most of the current crisis is focused: Crimea (including the city of Sebastopol) in the south, and Donetsk and Luhansk provinces in the east. All have Russian-speaking majorities, averaging 62%. But while the majority in Crimea identify as ethnically Russian, in the two eastern provinces only about 40% do.

That’s a consistent pattern across the country. Language and ethnicity are not the same: far more people (up to twice as many) speak Russian than actually identify themselves as Russian. So when Putin claims a mandate to protect not just Russians outside his country’s borders but Russian speakers, he’s casting the net very wide — as was pointed out by Geoffrey Pullum at Language Log.

The difference is clearest in the six southern provinces colored yellow. This area voted strongly for the pro-Russian candidate, Viktor Yanukovych, by margins of around three to one. Russian speakers are a minority, but a substantial one: 36% on average, and as high as 48% in Zaporizhia. By ethnicity, however, it’s much more obviously Ukrainian; the proportion identifying as Russian ranges from 14% to 26%.

More than half of Ukraine’s population is in the green and blue areas, which voted for Yulia Tymoshenko for president and where ethnic Russians are very thin on the ground: 13% in Kiev city, but less than 10% elsewhere. The green area, where Russian commands only about 3%, is the most Europeanised, having belonged to Poland, Czechoslovakia or Romania prior to 1939.

If Putin wanted to subjugate the whole of Ukraine, safeguarding the interests of Russians, even Russian speakers, was never going to be enough of a rationale. At most, that way of thinking leads to partition. Yet while Russia might be able to absorb Donetsk and Luhansk, moving beyond them, into territory where the overwhelming majority identify as Ukrainian, seems beyond the bounds of practicality.

On the other hand, all the signs so far are that — in contrast to Crimea, which is now clearly lost — Ukraine will not give up its easternmost provinces without a fight. And if Russia has to fight an actual war, it seems an awful lot of work to go to for just two provinces, amounting to less than a sixth of Ukraine’s population — no doubt at the cost of permanently alienating opinion in the rest of the country.

That makes me still think Putin is looking for some sort of settlement in which he can get concessions from Kiev, including recognition of the gains he’s already made, in return for reining in the separatists. As Damien Kingsbury said a fortnight ago, the annexation of Crimea is supposed to be “an object of lesson to the Kiev government for what could happen in eastern Ukraine … not necessarily a precursor to what will happen”.

The big question is whether separatism in Donetsk and Luhansk now has enough momentum that it will resist any such settlement and succumb only (if at all) to force. If so, Ukraine could be in for darker times to come.