threat. where history will be a pretext for border revision. and this is a receipt for disaster. >> one of the great unanswered questions in all of this is is why is vladimir putin bringing this to a head now? what's triggering him into making such moves at this particular point. for no apparent obvious reason. >> i see two reasons. one is that putin was not able to achieve his goal in ukraine by crippling ukraine. and using conflicts in the east. as a leverage to federalize ukraine and make it weak. and to slice it. this didn't work. ukraine was holing and building a viable partnership with the european union. nato and the united states. that's one reason. he really wants to rack ukraine. another one that russia feels it has enough power to compel nato