Few people are in any doubt that Putin is ruthless, despotic and capable of cruelty and oppression. However, stupid, rash or feckless he is not. To date he has only allowed a trickle of arms and support to eastern Ukraine - just enough to maintain a low level attritional combat geared at wearing down the will and resources of the Ukraine. He has the capacity and capability to take the entire Ukraine by force in two days - and as that country is not a NATO member, could gamble that the West would scream blue murder but not react militarily. But he will not do so. He will trickle enough aid to ensure that the 'rebels' creep forwards in baby steps.
The Septics in contrast have a long history of stupidity, rashness and fecklessness in foreign policy, and Kerry's posturing over Ukraine does nothing to diminish this reputation. We may also safely ignore hawkish and provocative incitements from those safe in the continental US, far away from the actual risk of war. All of which is known and understood by Hollande and Merkel. If the US pours in more arms, so will Putin. Death and destruction will escalate and territorial gains remain zero sum. The generals and their at-heel dags and idiots need to get back to their armchairs; guns are not the answer.
Nor will Putin launch a strike against the Baltic mini-states, and invading Poland is as far from his mind as an attack on Japan. The has-been ex-NATO boss squeaking away trying his best to talk-up a non existent threat is just piqued because his trespass into Russia's grain fields was discovered. Yes, NATO needs to be sufficiently strong, but Ukraine is not in NATO and will never be, at least within the current borders. That's another reason Putin is ensuring the low-level conflict; whilst it's going on, not even the western bit of Ukraine can join NATO.
There really is only one outcome; a partition of Ukraine, a new Russian - NATO border. And the sooner we get down to negotiating this the sooner the killing will stop.