This was rather predictable. In fact, it's surprising it didn't happen sooner while Crimea was leaving Ukraine.
Since those in the Western Ukraine are largely Ukrainian nationalists, it seems that Ukraine should be partitioned along Russian-ethnic lines. There certainly is no good reason to go to war over it.
The West shouldn't pretend and act all bothered. The West more than meddled in Ukraine for the sake of expanding the Atlanticist Empire rather than allowing Russia to join without being devastated by plutocrats seeking hyper-privatization.