From my understanding of the situation, it's actually the Russian speaking Eastern regions and Crimea that are keen on separating from the Western, agrarian regions which are more influenced by Polish culture.

Two drivers are behind this:
> financial - the East isn't keen on redistributing its wealth with the West
> military - Russian speakers (and Russia proper) are worried that the Western leaning Tymoshenko is intent on shutting the Black Sea Fleet in Crimea and integrating into NATO

Stupid or not, Yanukovich's posturing offers insight into the separatist political objectives of the Party of Regions, in particular now that Tymoshenko was voted in as PM by the Vrhovna Rada (by a 1 vote margin).