[mopsi]

Genocide is a part of that. People capable of leading a country (top politicians, lawyers, academics, businessmen, military leaders, etc) must be murdered so that there is no-one to lead the opposition to Russian rule. After WW2, former leadership of countries occupied by the Soviet Union was methodically exterminated the same way. After people capable of leading a nation are murdered and prohibitions of cultural practices are placed on the remaining, they begin to lose their group identity (language, religion, etc) until they cease to exist as an independent entity.

Many Native American tribes disappeared this way, for example. They weren't murdered to the last person. Instead, they were put into conditions that lead to their irreversible decline.