Where they would stop?
Where they would stop?
1) To rebuild the old USSR territory, he seems to consider ex soviet bloc countries to be wayward states, not independent countries.
2) To expand Russia so that the border it shares with NATO countries is narrower and anchored to a defensible barrier. To my (amateur) eyes, that would possibly be the Dnieper river, although other good choices might exist.
1 is largely ideological, 2 is based on the fact that Russia is facing both demographic collapse (particularly when you focus on ethnic Russians) and it has immense borders that are already very hard to garrison. Due to the layout of Europe, Putin could potentially drastically strengthen his western border with more territory, which might be imperative to do before the Russian population gets too small to garrison it’s current borders.