It's fairly simple, but let me spell it out: Putin would like the Crimea area to be favorable to Russia and is scared by the apparent ease with which the Ukraine and the rest of Europe have been approaching each other.

This will cut Russia off from one of their strategically more important harbors. So from a geopolitical point of view stirring this up was a fairly dumb mistake, the EU (and Obama) figured they could slip this one by but Putin found a way to foment unrest in the Ukraine at the expense of lots of lives.

Stability: good, global silly chess games: bad.

Putin will hang himself and his buddies too given enough rope and enough time. Yank his chain and he'll react, and he'll gain local popularity because of the general publics non-interest in world affairs. So in my not so humble opinion this is all just dumb war mongering and a potential set-back for 30 years or so of slowly improving relations and it will likely take decades again to recover the lost ground if we don't get a nice little war in the Ukraine, Crimea and Moldova region before then.

Which would lead to a bunch more nationalism in Russia, potentially a new cold war and a whole lot of lives lost besides.

That region is a very bad hotspot and to start moving chess pieces around there is about as stupid as encouraging Taiwan to finally really break off from the Chinese, Backing either Pakistan or India against the other or by sending arms and money to Tibet.

I'm sure my elected leaders think they know what they're doing but I fear they are simply not capable of thinking ahead far enough when it comes to consequences of actions.

And that includes your elected leaders as well.

I'm fully going on the assumption here that the lines of command reach all the way back to Russia, and I'm also very sure that they never ever thought they were downing a passenger jet. The fall-out from this will have extremely serious consequences (as it should) but I fear that a lot more lives could be lost if this situation is not handled properly. I know people all over the world and Ukraine is not an exception. My friend Dima (Dmitry) there lives in one part of the country and has family in the other. Another friend of mine is married to a lady from there. This is a lot closer to home for me than it probably is for you and it bugs me that people here pretend that the Ukraine is far away and that this will not affect 'us'.

Of course it will affect us, and the response so far has been just this side of dumb. The EU structurally underestimates the still very formidable military might of the former USSR, is living with a wounded bear on its doorstep and has now kicked this bear in the proverbial testicles.

Lots of people have already died as a consequence (including those in that plane) and it starts to become harder and harder to see a path to de-escalation.

Putins end-game (if I'm any judge of affairs like these, which I'm probably not) is that he'll 'keep the peace' because Europe can't afford it, which will result in permanent Russian army presence in fairly large numbers in the eastern part of the country, which will be a military backed re-affirmation of the former status quo.

And then Europe will have to back away from their plans of annexing the Ukraine, which they likely will do but not easily (they can't for political / image reasons).

This will still have all kinds of risks but it will at least extinguish the fuse. As long as the Russians are playing proxy there is still a way out of this, as soon as the gloves come off and they roll a few divisions into the Ukraine all hope of resolving the situation without an all-out confrontation with Russia will be lost. I highly doubt Europe and the US are both capable and have the political stamina to pull off such a confrontation.

Kids playing with fire.