aquilon:

Yes, unlike NATO, the U.S. government can fast-track decisions on use the military to "protect national interests". But making a case that Ukraine falls into this category in a war-weary country requires Houdini skills.

Practically, it may not require, but it is certainly much easier for a Republican President to make that case. At present Republican warmongering is conflicted by the desire to make Obama and the Democrats 'look weak' on defense. I would bet that Putin has taken that into account.

"It is not necessary to have hope in order to persevere."