Mearsheimer has been making the same arguments since at least 2014. Recent events have proved him largely correct, I think.
However, I was surprised with the irredentist speech Putin gave yesterday. He questioned the legitimacy of Ukraine as a country and characterized the policy of allowing nations of the former Russian Empire to become independent a major mistake. He thereby played right into the hands of the Western narrative that painted him as a reactionary nostalgic for the days of Imperial Russia.
So what? The neonazis the US supports in Belarus and Ukraine are using flags of regimes which were propped up in those places by the Germans in WW2 and did not even last 3 years. Who is the irredentist and revisionist here? To be honest I didn't like it when Putin annexed Crimea and I don't like the creation of these puppet states either. But I can certainly understand his motives. The Russians are fed up with the US and its NATO poodles. Would you prefer they let Poland and Ukraine rearm and attack them first? The Russians have seen this kind of movie before in the Russian Civil War period after WW1.
I wonder what the plan is with Belarus. Two weeks ago, Lukashenko said in an interview with a Russian journalist that he expects Putin to make him a colonel in the Russian army. Makes one wonder.
Putin wants it to submit to become part of the Russian Federation. Perhaps as an autonomous republic. He does not like the idea of the Union State. He thinks it is a repeat of the failed Soviet model with separate nationalities. At least that is what I got from talks between the two a couple years ago. Back then Putin was getting fed up with Lukashenko since Belarus was buying oil at special discount refining it and reselling it. Russia cut the amount of oil and gas Belarus can buy steeply. The discount was supposed to be for their own use, not to compete against Russia in exports. Russia started building new refining and distillation facilities and a new port in the Leningrad region at Ust-Luga to cut out Belarus and the Baltics as middlemen for Russian energy. They were fattening themselves up by reselling Russian energy they get at steep discount on international markets. They have all been doing this since the fall of the Soviet Union. The Baltics even do this while spewing venom at Russia. The Russian government got fed up with this.
As a sort of compensation Belarus asked for Russia to build them nuclear power plants so they can reduce their gas imports. The Russians built one reactor and are building the second reactor. Belarus got a low interest loan which they will pay over 20+ years and they only need to pay once the reactors become operational.
More things are likely to happen as the Ukraine is now incredibly unstable with its Government abandoning Kiev and relocating itself to Lvov. Add to this that the Ukrainian army is fully aware it is on its own and that now Russian forces are openly operating on disputed territory outside of the Crimea.
The likelihood of other parts of the East of the Country to start falling apart in a full process of Balkanisation is very high and only a diplomatic security agreement, along the lines of that proposed by the Russians has any real chance of halting this process.
Remains to be seen. Had Russia done this in 2014 it might have happened. But the Ukraine government forces had a long time to "pacify" this kind of sentiment since. I doubt there will be any spontaneous movements in the borders. In fact I think it is way more likely the central government itself will collapse. Remember only a couple weeks ago Poroshenko was agitating people and instigating protests in Kiev.
So full Russian invasion still looking very very remote. The prospect of the Russian Army expanding into new disputed areas on R2P peace keeping missions look highly probably.
This would be basically turning the US's own model against them. Yes it might happen.
This guy is somewhat popular in Russian political circles.