Honestly, despite all of the rhetoric coming from all sides and pleas for peace, there is an actual unwillingness to do anything besides play blame game. The results are a lot like Jugoslavia, talks about talks, harsh words, all the while people die.
As for the back story, what is the situation throughout the world? Meaning how much can NATO, mainly the U.S. afford to commit to Ukraine? Is there still a campaign against ISIS? What of GWOT? Or is Ukraine war happening in a vacuum? I saw written USMC invasion near Odessa or in Crimea, how was the massive land based (in Russia proper) ASM threat dealt with for sending ships into Black Sea?