I was recently referred to this article (English translation), which put Russia's actions in Ukraine in the broader context of global geopolitical maneuvering. This type of big-picture realpolitik analysis almost never makes the news, so I think many readers will find it very instructional, as have I.
For instance, the author makes that point that Russia is very concerned about the U.S.'s ability to disable most of its nuclear weapons through long-range missiles and deployment of PRO anti-missile systems near Russia. Taking over part of Ukraine's territory would give Russia much better striking capabilities against U.S. allies in Europe, decreasing the likelihood that the U.S. would engage in a unilateral punitive strike against Russia.
The idea that Russia might be working towards an eventual continental alliance with Germany was also news to me.
Basically, I highly recommend this article.