They did in WW2 didn’t they?
Poland was on their border then. Belarus serves as the buffer state today. So no, with all off Poland’s armor and all of the rest of NATO’s to be quickly committed, NATO would still have to fight across 400 miles of Belarus to be in the same position Ukraine would be in from the get go. That is why Ukraine as a NATO member is so incredibly destabilizing. Again, NATO membership crazy talk from Belarus would put them in the same position Ukraine is in today.