>>514876965
Baltic states combined have 6-7 million people. Russians will invade with no less than 1 million troops and to repent them NATO will need as many soldiers on ground.

Only way to move this mass in case of Russian invasion is to make similar ground "invasion". That's why construction of Via Baltica accelerated lately. Russians could try to cut it off (famous Suwałki Gap - basically southern Lithuania), but from what somebody told me, these plans always revolved around US forces being away from there (not in Poland) for some reason that has sense in Russian mind.