^ As if Ukraine wouldn't become a member of NATO in a heartbeat if it went it's way. Putin's interest in Ukraine is about whether he gets to park his gunboats in Sevastopolj or if someone else has that right. He'll probably grab what else he can get to have a bit of land for connection, defense & supply lines, but might even not. He certainly doesn't need to have a war in Ukraine, and here's why:
Disclaimer: Apology to any decent folks from the EU, you guys just live your lives and aren't accountable for anything. It's about your political/financial elites.
Putin gets Crimea (and whoever else votes to join him), rest of Ukraine goes "free". If it manages to join the EU it'll take a while, but Ukraine's economy is about 100% dependent on Russia. EU is all about destroying the economy of it's colonies - ask any non central-european country, and ask any country which decided not to join it. Most of their power structures and don't actually KNOW how to improve an economy, most of it is based on near-slave labor from countries like Ukraine allready in the EU, import of raw unprocessed goods from these countries and selling them back their own stuff unprocessed or processed. This is what's been going on in Croatia for the past... god knows how long, and seems to be what is happening everywhere outside of the core founding countries of the EU.
The EU can send financial help, but a big part of that is going to get allocated the way the local political elite wants, IE stolen. The previous political elite (Janukovich) is going to be blamed for the "crisis". If the EU helps in any way, most of the help is going to line politico's pockets, you can be 100% sure of that. Is this any worse than it was with Janukovich?
Well, no, but there IS a catch, and that catch is why Janukovich decided to bail on the deal with the EU and turn towards Russians - he figured out that what Ukraine was going to get from the EU would probably be enough to keep him lining his pockets, but would actually be waaaaay less than he was getting from Russia. The country is allready in deep s**t as far as anyone can tell, and he wasn't getting all that much from Russia - but he was getting just barely enough that if he steals most of it and most of the proffits, at least the country doesn't collapse completely.
So now the new guys will be in the position in which Janukovich would've been had he completed his deal with the EU, except they won't have his bargaining chip for mollifying Russia into letting Ukraine at least export and have some gas. That was Sevastopolj. Putin really, trully doesn't give a rat's ass about Ukraine other than the strategic spots. Now that he has Crimea, he'll probably just kiss the rest goodbye along with all the expenses of maintaining a non-proffit oligarchy and have one less worry in his life (maybe he'll take some more land, but very dieffinitely not the whole of Ukraine - he'd gladly let the western half go). It'll be a never ending supply of press topics for his media machine and serve nicely to keep the people occupied, and it won't cost him a dime.
And the Ukraine that splits from Russia won't find any joy in Europe. A lot of people will emigrate at the first opportunity and be low level wage slaves or service industry slaves in the west. Winter will come around and there will probably be even worse protests than there were this year - the EU has not in fact sucessfully helped a country ever, and it's can't and wont. One of the main things which was all over the papers in Croatia for 10 years was how political corruption is going to end once we get into EU (Yanukovich style political corruption). Turns out that everything from the economic crisis in Yougoslavia, to the war to every single instance of unbelievable corruption in Croatia throughout my whole life was... just a small scale backwater operation for EU tycoons. Tons of it is out in the open (especially since Jorg Heider died so he became an acceptable target), except there's noone to process anything - they own all the courts.
The Gremans own the local telecomunications and charge the highest ammount in Europe for impulses, all the banks have been sold to foreigners, 95% of the factories have been systematicaly dismantled, big hotels were being devastated just so that Europeans could buy them for insanely low prices, we produce enough food to feed the country many times over, but we IMPORT food from the EU, imported cigarretes cost less to buy than localy produced ones (and only the price of the local ones goes up whenever EU passess an anti-tobacco bill), running any sort of bussiness is impossible because of all the laws and adjustment we were forced to adopt, while "non-proffit organizations" funded by the EU pay no taxes, mayor goverment projects are undertaken only with the blessing of foreign bank owners - the goverment officals take huge gratf, to both steal for themselves AND inflate the costs, and the banks lend money at ridiculous interest that keeps pushing the country more and more into debt which is then repayed by giving away more terrain and infrastructure. We built a highway at 27 (!) times more than it costs, and the interest on that loan makes it so unproffitable that we're forced to sell it to the foreign banks - and during summer half of Europe seems to pass throught the toll booths on that highway since we're a big tourist destination (and it leads south towards Greece and Turkey). Oh, and since we joined, there's no entry fee into our country, so our tourism took a large hit there as well. Oh, and importing stuff is easier than ever. Oh, and a huge proffit is being made by foreign pharmaceutical companies, I know this from very personal experience, but all the pharma companies are rutinely bribing doctors to perscribe their products (that's all their marketing departments do, in fact, even though it's illegal). There's about 20 of them, and they're all doing it - but the only companies which get fined for it are the few local ones (dismantling of a local company for corruption was a big media circus last year, my friends in the pharma biz were rolling their eyes about how every single pharma company could be destroyed in an afternoon on those charges, but no politician would touch EU companies because their only job is to make sure noone interfears with the systematic robbery commited daily by them.) We have 400.000 unemployed in a country of 4.000.000 and our goverment got payed to pass a set of laws which let employers lay people off even more easily, and then bailed a ton of foreign firms out of private debt (including their entire propaganda machine) with the money that came out of the countries budget by taking out even more loans from foreign banks. Goverment departments are contracted to buy new "cars parks" from EU manufacturers every year at exorbitant costs. Food produced and processed in Croatia is more expensive in Croatia than in Germany. Too many families live off the grandparents pensions, and those pensions were earned while there was anywhere to earn them in - once that generation dies, there will be actual, real hunger. Bosnians, also in their sphere of influence, burned goverment skyscrapers a month or so ago - in about 5 or 10 years you can expect the same and worse here, but all due to the EU. I could go on for days, it's quite unbelievable, they hardly even bother to hide it anymore... There is not one single thing the EU is good for, short or long term - they have nothing at all to offer.
I suppose Russians are quite as bad, but I've felt the EU and no sane group of people would want anything to do with them if it at all could be avoided. Heck, even scum like Janukovich decided that they were the worse deal, and immagine how bad a deal they are when Putin seems like a clearly better option. Had it not been for the demonstrations, his bargaining to get more out of Putin because EU offered anything was actually a stroke of genious. The only way membership in the EU could possibly benefit anyone in Ukraine is if they're all allowed to leave the country at once, which they won't be because they'd flood the allready strained job market. So, as I said, come winter, there'll be a lot of pissed off Ukrainians even worse off than they were before - because now Russia really has no reason to even talk to them, but can deny them access to the Russian market or turn their gas off whenever it wants (Putin did so before I think). Russia's got that on the EU - they can actually give you access to their market, and they can sell you gas.
Only, if there's new riots next year, Putin might sponsor the new rioters, just for the heck of it...