They won't unless they have no other choice .. and that is still in question
I'd like to see the former captive nations unite and reinforce Georgia. A united Lithuania, Latvia, Estonia, Romania, Bulgaria and most of all POLAND would start to be an effective counter to Russian ambition.
This would have great moral power because it would demonstrate solidarity among all those nations that were held captive by the Russians for 50 to 100 years. \
While the militaries of those countries, except Poland, are pretty small it would still send a powerful message.