james, can you explain to me the motivations of the US and Russia's involvement in this situation? I've so far had a hard time wrapping my head around that part. Your post indicates a perception of Putin acting out of greed (a trait of being evil) and I just want to know how it's different from what everyone else is doing there.
Putin is in a fight for his ego. His propaganda reveals his self-image. To maintain his identity, he must not back down, must out-game all opponents, and make continual gains. This is perfectly aligned with his domestic political requirements. Expanding empire is good for the oligarchs he represents and manages, and good for his popular support. His most obvious weakness: Dependence on internal backers, whose interests may change skew to his own. We have a mafioso in power in Russia. He's more like Don Corleone than Hitler, but there are similarities to both.
Russian invasion of Ukraine at SOME level will not be tolerated by NATO. He has seized Abkhazia and South Ossetia. He has seized Transdneistra. He has seized Crimea. If he seizes Ukraine it seems clear he will seize the Baltic States. Hell, why not Finland? Why not assimilate Kazakhstan, Uzbekistan, Kyrgyzstan? We've been down this road before. Poland in WW2 had its borders guaranteed by UK. Ukraine today had its borders guaranteed by US UK and RU. If Russia stays in Ukraine, Ukraine will re-arm nuclear. NATO does not want that, at least not unless Ukraine is both stable and part of NATO. Putin would rather invade Ukraine entire than invade part and face a nuclear Ukraine in 2 years time.
To say there is nothing the west can do about it seems very questionable to me. Putin can be removed. Economic measures can be taken which would beggar Russia, causing him to be deposed. Military action can be taken to strengthen Ukraine. Political action can be taken, to incorporate Ukraine into NATO, or offer that as a chip to bargain against Crimea. In a political game, ground truth is critical. Putin is motivated to grab as much as he can before coming to the bargaining table. If he does that badly, there will be copious blood. The west has strong incentives to stop him before he gains more power, more momentum, and more bargaining chips. In fact, given his history, it seems clear to me at least that he must be punished. Some chips must be removed from his kitty, or he will just do it again on another front.