Of course, getting more people can be done in ways other than inducing Russians to have more babies or encouraging people to immigrate to Russia. You can push the border past the people you want.
UPDATE: I'm not impressed with this denial, insisting that Putin isn't trying to restore the Soviet Union:
In the West, Putin’s best-remembered statement about the Soviet Union described its end as the “greatest catastrophe of the twentieth century.” But Putin’s other comments, less familiar to Western readers, refer to the Soviet system as “unviable.” In his ruthless judgment, those who want the USSR back “have no brains.”
Twenty years after the loss of its twentieth-century empire, Russia is ready to move toward a new kind of integration with its ex-provinces. This is not intended as a threat to others; rather, economic integration is a test of how much Russia has learned about the world since 1991, and of how much more modern it has become as a result.
Fine. Putin isn't trying to restore a union of soviet socialist republics. He's trying to restore the czarist Russian Empire.
When your defense of Russia is reduced to an earnest debate about what the definition of "is" is, you're losing the debate.
