Russia does not require an invasion, only a zone of influence in the Intermarium that it can achieve by gradually compromising the democratic vitality of rimland states. {Hungary, in particular, is well on its way in this regard.}
In his book, Robert D. Kaplan discusses Russia's strategy regarding the Intermarium region, highlighting that it doesn't need to resort to military invasions. Instead, Russia can expand its influence by undermining the democratic structures of the surrounding states. This gradual erosion of democracy allows Russia to exert control without direct confrontation.
Kaplan particularly points to Hungary as a significant example of this trend. The country appears to be moving away from democratic principles, which aligns with Russia's objectives in the region. By fostering such environments in neighboring states, Russia aims to create a sphere of influence that strengthens its geopolitical standing in the twenty-first century.