I think your question contains a false premise.
Just as a qualifier—I don’t think any state is legitimate, and all the sides involved are utterly degenerate and contemptible.
I don’t think Putin has any territorial ambitions, and would have preferred the status quo before the deposition of Yanukovych and not have to deal with all the diplomatic and political fallout.
Yanukovych was courted by the EU, but the EU never presented a concrete proposal or reasonable deal. Putin stepped in and offered a few billion in roubles and gas at ⅓rd the price. And out of the window went any chance of EU membership.
That is until a right-wing coup deposed Yanukovych—there’s some evidence now that the protests were hijacked by right-wing groups, who went so far as to use snipers to kill protesters and then blame it on Yanukovych. Now Ukraine has a regime that is now all too eager to take IMF loans (that’ll work out well) and join NATO and even the EU, and is hostile to Russian interests.
And why would Putin tolerate that? The US has simply not ended the Cold War. NATO has expanded eastward, missile defence shields are to be installed in Poland, and funding for anti-Russian groups in the Ukraine have gone on for years.
I think if the Ukraine breaks apart any more, it’ll be from within the Ukraine with little pushing from Russia.
@Symbeline Completely implausible. The pretext for annexing Crimea was based on the existence of the anti-Russian government in Kiev. How could they possibly plan something based on an event that they neither desired nor could anticipate?
@antimatter No gas lines run through Crimea.