The facts are that immediately after the MH17 downing news broke Putin started frantically calling all major leaders. Next thing everyone expected was some real action from the US and the EU. Not only the US was cautious about the MH17 conclusions, they almost tried to help Putin get out of all this. The same did the EU only talking about the sanctions and doing nothing in reality.
The reason behind Putin's calls was to explain that it wasn't him who gave the orders to shoot the plane. Moreover, it was not his decision to send Buks to the separatists.
And that may be true. Putin's chair seems to be balancing, and he does not full control of the situation in the Ukraine's east and potentially in Russia either. And the US/EU know about that. Options? Putin clearly states that those who want to overthrow him, are much more aggressive towards the West, and they will try to resurrect the USSR starting from Ukraine.
Also, the first phrase said by Putin on the Security Council was "Of course, there is no threat to the territorial integrity of Russian Federation at this moment". That may be another indication of the background game: "We all are safe when I am the President. Leave me behind - and you will have major problems!"
Yes, Putin has popular support of up to 85%. But will these people fight for him? Majority of Putin supporters are socially passive recipients of government funds, so a negative answer is no surprise. Putin's opposition can be Army or the Ministry of interior (or both), neither of which would hesitate shooting at Russia's own people as they are doing with Ukrainians.
Therefore, the US/EU are waiting to see whether Putin can handle the situation. And it seems he cannot, at least, from the Americans point of view. The US already have started to "drown" Putin by directly accusing him in involvement into the high-precision weapon supply to the separatists in Ukraine.
The situation is volatile for Ukraine. But it is even so for Putin. The fight in the Kremlin continues. Look at the situation from this angle, and many things will make sense.