It is easy to start a war; impossible to predict it's end.
We learned this the hard way in Korea, Vietnam, Iraq and Afghanistan. Putin rules Russia with a bloody fist and it appears launching this war is his personal quest to seize Ukraine.
Fiona Hill spent years as an intelligence officer on Russia and Eurasian affairs for Presidents George W. Bush and Barack Obama then served on the National Security Council under President Donald Trump. She has studied Putin for years. Fluent in Russian she was usually in the room when our Presidents met with Putin. It is her observation that Putin is personally obsessed with recreating the Soviet Union and reestablishing Russian military and political dominance over Europe. She believes he attacked Ukraine now because he sees The United States as "grievously weakened at home and in retreat abroad".
Considering NATO nothing more than an extension of a weakened United States Putin appears surprised by the opposition President Biden generated from NATO and other European nations. Actually their opposition makes sense in terms of self-preservation. Having watched Putin conquer Georgia, Crimea and Eastern Ukraine his goals are obvious.
Russia does have overwhelming military capability which ought to make destroying Ukraine easy. What The United States learned in Vietnam, Iraq and Afghanistan is that occupation during an ongoing insurrection is endless, bloody, expensive and impossible to win.
While Putin has frequently demonstrated his willingness to kill people and destroy cities NATO response to this invasion is bankrupting Russia. Other than selling oil Russian has almost no source of income and assets stashed away in banks are frozen. If NATO holds together living in Russia will be a life of extreme poverty.
Perhaps worse for Putin is that his Oligarch supporters are now denied access to their ill-gotten wealth. They and their families can no longer do anything but sit home in their cold Russian houses. Ideally the Oligarchs and others will foment regime change; sane people will depose Putin and reason will prevail. His face is puffy and he has visibly aged so nature may intervene. But Putin may survive.
If Putin survives, and cannot win outright, he may wall-off Donetsk and Luhansk in Eastern Ukraine and then use them as a base to foment turmoil in Ukraine, across the borders of nearby nations wherever opportunity arises and there is an exponentially worse scenario.
Putin appears to consider himself and Russia one and the same and he has nuclear weapons. Over the past eighty years I have seen humiliated, enraged men do incredibly self-destructive things. Fiona Hill was in the room when Putin stated his intentions.
In her words "In one of the last meetings between Putin and Trump when I was there, Putin was making the point that: "Well you know, Donald, we have these hypersonic missiles." And Trump was saying, "Well, we will get them too." Putin was saying, "Well, yes, you will get them eventually, but we've got them first." There was menace in this exchange. Putin was putting us on notice that if push came to shove in some confrontational environment that the nuclear option would be on the table."
What Putin is doing in Ukraine does concern us here.