Snorrius
Librivorator
Errr... You are approaching this from a brainwashed point of view but I will try to make it clear. The problem of Kazakhstan is that it for centuries was between two strong states - Russia and China, so it have to lean to one or another. And historical experience shows that becoming part of China is a path to fast and cruel assimilation.Why would Kazakhstan join in Union with Russia? The Russians have been pilfering money from central Asia for Mother Russia for centuries now! And now that Kazakhstan has a strong Kazakh majority, there is no way in hell it would sit there and wait for Russia to redirect cash from Kazakh lands. Plus, I was under the impression that the Central Asia states see Russia as an economic friend and a political threat.
Another thing is that "pilfering money" is quite a mistake. Unlike, say, modern US which just keeps sucking real resources from the world in exchange to freshly printed dollars and generally avoid to develop countries they control, Russian Empire or Soviet Union actually make a lot direct investments into development of its "internal colonies" and allies.
If we are talking about modern customs union - than it is obvious. It is impossible for Kazakhstan and Belarus to keep their economy afloat without economic integration with Russia. Making common economic space will also help to reap mutual benefits. From the military point of view it is the same - nor Kazakhstan, nor Belarus have not real power to protect themselves. At the other side, unprotected Kazakhstan and Belarus is the threat to Russia, so cooperation is necessary.