What Does Russia have left to Attack Poland during the Invasion of Ukraine?

The Russian invasion of Ukraine has predictably fixed a substantial proportion of the Russian Armed Forces. Russian forces are not fighting as battalion tactical groups (BTGs), but this remains the manner in which both the Russians [1] and the Ukrainians [2] are administratively assigning troop movements. As such, this overview will use this denominator as well, though again the evidence from the war suggests that the primary unit of tactical engagement will not be the BTG per se.