Russia intervened in Donbass in 2014 (primarily with cross-border artillery and material aid, and possibly spotters and liaisons) to defend Donbass from Kiev.
The Russian military takeover of Crimea which allowed a Crimean independence referendum galvanized a previously glum and resigned Donbass into rising up with the aim of securing the same outcome of breaking off from Kiev and joining Russia for themselves.
This was a development that caught Kremlin completely by surprise. Rather than order the Russian military to take control of Donbass as it had done in Crimea, Moscow quashed their hopes and came up with the formulation of “Crimea is Russia, Donbass is Ukraine” that was put on an endless loop.
Nonetheless, Moscow expected Donbass would be allowed a measure of autonomy and would be reincorporated under Kiev behind a green table. When post-coup Kiev moved to subdue Donbass by force instead, Russia eventually struck against the coup-government forces — but only just enough to prevent their victory and to force them to abandon their offensive and the hope of a military resolution.
So to repeat, from Russia’s position the 2014 war was a very minor one and with very limited goals — to prevent the Kiev putschists from rolling over a region which had rejected them.
There is now currently great anxiety and unease in Washington as they’ve come to realize that should another war break out in the area Russia’s war goals won’t be nearly so limited:
The agency also worried that the potential conflict zone didn’t appear to be just the eastern sliver of Ukraine occupied by Russian-backed separatists, which Russian troops had approached the previous April, but a much broader swath of the country. Alarm bells rang at the agency, and then across the U.S. government.
NATO’s slow but unrelenting tip-toeing ever deeper into Ukraine means the strategic conundrum for Moscow is no longer protecting Donbass from Kiev, but securing Russia itself against NATO. Should the next war come Moscow’s war goal will not be to rebuff the advance of Ukrainians but to freeze the advance of NATO.
I don’t think the Russian government wants war. In fact, a war would all but guarantee that NATO would move into whatever remained of Ukraine after it even faster.
An agreement would be much preferable. However, the continuation of NATO’s Drang Nach Osten that will eventually see them setting up Canadian training facilities in a city as Russian as Kharkov isn’t tolerable:
President Vladimir Putin said on Tuesday that Russia would be forced to act if its “red lines” on Ukraine were crossed by NATO, saying Moscow would view the deployment of certain offensive missile capabilities on Ukrainian soil as a trigger.
Meanwhile, with Belarusian relations with the West lower than even during the days of the “Outpost of Tyranny” Lukashenko is valuing the fact Russia has his back military more than ever.
The fact he now “owes one” to Russia reshuffles the chessboard considerably. This, on the other hand, is what is causing anxiety in Kiev.
There are no Russian ground troops in Belarus that we know of. (Only a handful of jet fighters in the Baranovichi airbase.) But if that were to ever change then any conflict would kick off with the Ukrainians surrounded on three sides. Moreover, Kiev is just 200 kilometers from the Belarusian border.