The problem here is (again) that nobody wants to make Putin angry. Or sad. Or generally unhappy in any way whatsoever. I mean, nobody from the West. Russia basically says "Do what we want or we will do what we want anyway." And Obama and... Whoever it was on EU side just reply "Dude, that's not nice! But oh well, OK, if you insist. Just don't kick us in the nuts." That's a wrong way to go about it. It was wrong to begin with; on the first sign of Russian invasion of Crimea, NATO should be all like 'Hey, get out of there'. There should be a freaking aircraft carrier on the Black Sea, along with all the companions, not a single destroyer; offer of military assistance aimed at Ukraine as soon as any kind of invasion become even possible, and actual American* troops flying into Crimea way before the 'referendum'. Why? Because:
a) USA guaranteed that the Ukraine will stay intact after giving up nuclear weapons;
b) it is pretty much obvious to anybody with half a brain that _not_ doing that will just make Putin want more.
But it's not like the US can take any of it's military operations to the end. Not in Afghanistan, not in Iraq, not to mention things like Libya or Syria, so I wouldn't expect any better this time. Or next time.
Well, it will generally accomplish one thing - everybody will either give up or stack up military stuff. There are already voices in the Ukraine that the country should get some nukes back; in Poland there are talks about upping the army expenses, and so on.
*Yeah, I moved from NATO to just USA there, because let's admit it, it's not like the rest of the NATO could do much. As far as the EU goes, there is so little will to fight at all, that if not for the Americans, Russia would steamroll all the continent to Lisbon with less resistance than Hitler, due to populations just... Giving up. And the politicians are even worse here.
While I'll admit that we have had some problems with planning on an end game for the recent wars, we never had boots on the ground in Libya or Syria, the Iraq war ended (took Obama to end it though) and the Afghanistan one is ending at some point this year.
As for Russia steamrolling Europe all the way to Lisbon, come on, that is just BS. You're from Poland, right?, do you even think Poland is going to sit there and let their country get steamrolled again for the nth time? Somehow, I think you just called your own countrymen cowards. I can see France being a surrender monkey, but Germany? Italy? Austria? Hungary? The Balkan states?
The EU doesn't want to get into a war if they can't help it, but not wanting to get themselves into a war doesn't mean that they won't fight back if they have to.