Putin is probably trying to calculate what's the most he can take consistent with keeping the probability of a major war with the United States below some level. If the U.S. is unwilling to fight, Putin will take all of the territory of the Soviet Empire + perhaps Finland, a country that used to belong to Russia.
Currently, he only seems interested in territories inhabited by ethnic Russians, who are happy to be (re-)annexed to the country they consider they homeland.
I doubt he is much interested in taking, say, the Baltic republics or cis-Dniestr Moldova, as he would have to rule there with an iron fist on an uncooperative population.
Currently, he only seems interested in territories inhabited by ethnic Russians
Currently that is all he is openly or semi-openly taking action on. As for what he is interested in, he is on record as calling the collapse of the Soviet Union "a major geopolitical disaster of the century". It seems clear that he wants to restore all of that territory. All else is tactics.
I doubt he is much interested in taking, say, the Baltic republics or cis-Dniestr Moldova, as he would have to rule there with an iron fist on an uncooperative population.
Rul...
Some of the comments on the link by James_Miller exactly six months ago provided very specific estimates of how the events might turn out:
James_Miller:
Me:
"Russians intervening militarily" could be anything from posturing to weapon shipments to a surgical strike to a Czechoslovakia-style tank-roll or Afghanistan invasion. My guess that the odds of the latter is below 5%.
A bet between James_Miller and solipsist:
I will bet you $20 U.S. (mine) vs $100 (yours) that Russian tanks will be involved in combat in the Ukraine within 60 days. So in 60 days I will pay you $20 if I lose the bet, but you pay me $100 if I win.
While it is hard to do any meaningful calibration based on a single event, there must be lessons to learn from it. Given that Russian armored columns are said to capture key Ukrainian towns today, the first part of James_Miller's prediction has come true, even if it took 3 times longer than he estimated.
Note that even the most pessimistic person in that conversation (James) was probably too optimistic. My estimate of 5% appears way too low in retrospect, and I would probably bump it to 50% for a similar event in the future.
Now, given that the first prediction came true, how would one reevaluate the odds of the two further escalations he listed? I still feel that there is no way there will be a "conventional battle" between Russia and NATO, but having just been proven wrong makes me doubt my assumptions. If anything, maybe I should give more weight to what James_Miller (or at least Dan Carlin) has to say on the issue. And if I had any skin in the game, I would probably be even more cautious.