I read the Peter Zeihan books last year. He discusses the issues Russia has had with defense of its Western border due to bad geography. Never had a reason to give much thought to this, but was interested in how geography helps or hurts a country in terms of defense. And then almost to the day of Zeihan's prediction, Russia invaded Ukraine.

There is a good paper here that discusses this in detail including the use of security services and the horrible shit the Russian government has inflicted on its population and neighbors in the name of homeland defense.