I've become convinced that for Russia to make any diplomatic gains, it must undertake military action of some sort. Unfortunately, given that the West has publicly stated that it would inflict as much damage as it can if Russia takes any action, the incentive for Russia is to go for maximalist military action since it's going to pay the same price no matter what it does. It's worth thinking about how that might play out.
Of course, Russia would love to be able to capture all of Ukraine in a lightning campaign and install a puppet government before anyone has a chance to blink. Unfortunately, the Ukrainian military - while weak - isn't that weak, the political system is sufficiently cohesive, and the population is sufficiently hostile to make that infeasible. What's likely to happen in the broadest range of military scenarios is that Ukraine becomes another Syria.
What I think will eventually happen is that Russia will seize southern and eastern Ukraine (the "Novorossiya" region) and establish a quasi-functioning state there. No/sporadic insurgency, a government that provides basic services, integration into the Russian economy, etc. It would be far better than the parts of Syria under Assad's control today, but still far from prosperous. The northwest part of Ukraine would be Idlib in this scenario - frequent Russian bombardment, massive refugee inflows (from the populations exiled from the parts of Ukraine under Russian control) and outflows into countries like Poland, a destroyed infrastructure incapable of supporting human habitation, etc.
We might get there quickly or we might get there over a period of years if this conflict drags out and the West stays committed to its sanctions policy and severs ties with Russia, leaving Russia no choice but maximal, unconstrained hostility against the West.
