Unless something goes horribly wrong, no shots will be exchanged between anyone from NATO and the Russian army over this. The reaction will be to make Putin see this as a horrible strategic mistake. While NATO allies will certainly be part of this, a speech about another reset to relations from Obama would carry far more weight than a similar one from the French, Germans, or UKians. Some other things that could be announced in the next week or so would be:

1) Restarting the missile shield in Poland
2) Green lighting natural gas exports
3) Expanding a few bases in places where Russia would not like to see them
4) Making it a priority to close Russia's base in Syria

Russia is naturally given to paranoia, the US can exploit this in ways that our European allies can't, without firing a shot.