“The West is leading Ukraine down the primrose path,” Mearsheimer averred in 2015, “and the end result is that Ukraine is going to get wrecked.”
https://www.nytimes.com/2022/03/09/opinion/ukraine-russia-in...
A sect of realpolitik theorists outlined why Russia would be compelled to invade Ukraine. Even Kissinger thought that expansion of NATO westward would compel war with Russia. To say no one predicted this or that it’s self-defeating for Russia is a mistake of analysis. The war logically follows from Russia’s security goals.
According to Kozyrev, instead of a patchwork of dysfunctional countries at war with each other like in the former Yugoslavia (with overspilling effects on Russia), EU and NATO integration helped build modern, peaceful and predictable countries in Central and Eastern Europe, which in practical terms meant "free-of-charge security" (his term) for Russia. What's there to complain about?
Furthermore, Mearsheimer et al treat countries as monoliths and completely ignore the competing interests of groups and individuals within them. Russia of the early 1990s was a flawed democracy; today it is a totalitarian dictatorship. The war against Ukraine is a downstream effect of the destruction of Russian democracy and consolidation of absolute power into the hands of Putin's security apparatus gang. Putin wants to be remembered as a "great ruler" and that's all there is to it; a small man who managed to gain absolute power, no different from Hitler.