AFAICS, it's all the same to him: If he were dreaming only of reviving the Tsarist (why "pre-"?) Russian Empire and not the Soviet Union, he'd hardly have gone on the record saying "the fall of the Soviet Union was the greatest geopolitical tragedy of thetwentieth century".
He is thinking about the pre-Tsarist Russian Empire. Which included a few countries that were not in the USSR.