comment: >
  
  I dunno about cut off. More likely just immediately overrun
context: Lithuania has some really good reasoning for that too. Mainly it's next to Russia's exclave and Belarus. >
  
  Exactly this. Kaliningrad and their close proximity to Belarus effectively make them cut off from the rest of the NATO country, should a war break out. The only way would be to support them via the sea (and air). >
  
  Lithuania also borders Poland. >
  
  It's only 100km wide though. Lithuania - Kaliningrad border is almost 3 times longer, and Lithuania - Belarus border is 6.7 times longer.
  If war breaks out, and Belarusian / Russian / Soviet troops starts from Grondo to meet up with troops from Kaliningrad, Lithuania (and Estonia / Latvia) would be cut off.