I thought I'd add one more scholarly look at the basket-case which is the Ukraine/Black Sea region. The author lays out some of the history of the region as well as the less-admirable aspects of US involvement.

Another way to look at it is the Cuban Missile Crisis - just reversed. Can anyone really fault Putin for not wanting HIMARS systems - potentially nuclear tipped - right off his border and especially in a region which has been affiliated with Russia for hundreds of years?