Demographic Shifts in Russia may be exaggerated but it is not exaggerating that they have a few parts that are basically Muslim like Chechnya and have about 2 million Muslims in Moscow alone according to these references: http://www.danielpipes.org/blog/2005/08/predicting-a-majority-muslim-russia So this could become a problem down the road. Russia is so big and Chechnya and Dagestan are on the edges of their country, they really don’t need them.
The Russian Muslim population is about equal to our Black and Jewish, and Muslim population combined, in percentage, and growing extremely rapidly.