It's a shame the US, NATO, and the EU couldn't find a way to peacekeep, but NATO isn't going to defend Ukraine. I doubt it would defend Estonia. The military isn't to keep the peace, and if Russia attempts the same imperialist strategies as the West it will fail.

What you're pushing is a full scale war in Europe, and the point of NATO was to keep the peace, but they failed a long time ago. Unfortunately, I don't doubt European nations will be at war with each other again soon, and you'll get your wish, but it's going to be fucking awful. Ugh

Just wait until European nations build their own militaries. That'll be interesting while sharing a currency.