I looked at item .1 in comment #3 about Russian Bridge and Tunnels. It was followed by a 43+ minute video on “What Is Putin’s Endgame.” The video link is below. I only watched a few minutes but it appears detailed and well made. I will watch the rest of it on Friday.
https://www.youtube.com/watch?v=cAh9mbw1J68
The back door is open all the way to Moscow.
Crimea...If you want to look at how bleak the Russian security situation is, consider Crimea and the Black Sea Fleet.
Ducks in a pond, with two tiny passages out. Dead ducks walk’n ...er floating.