In an a NATO-Russian conflict, having free movement of Russian troops through Belarus means you only have a 50 mile gap to fight through to link up with Kalinin

In an a NATO-Russian conflict, having free movement of Russian troops through Belarus means you only have a 50 mile gap to fight through to link up with Kaliningrad, as opposed to over 300 miles directly from the rest of Russia. At 50 miles Kaliningrad and Russian forces fighting from Belarus could have overlapping SAM cover and MLRS artillery support, it's well within the combat radius of attack helicopters, etc. And there are railway lines around that corridor that, once seized, would enable efficient transport of material.