Until we as two superpowers, dismantle our Nuclear Arsenals, there ought not be Conflict Pushed Forward!
The foreign policy of the U.S., which has arisen from liberal educator's thought, and preached from University Lecterns for over thirty years; involves push push, intimidate, grab what you can, don't worry about the other guy, just do what gains US the most, and forget about the consequences! Our U.S. President is very much a student and product of the atheistic liberal Education System!
Since the fall of Communism in Russia, NATO has already advanced into Poland, Bulgaria, Romania, Slovakia. etc. Ukraine is less than three hundred miles from Moscow. What would be the consensus in Washington if Russia and the Warsaw Pact would be pushing it's way into South Carolina? Basically Russia is a landlocked nation except for a warm weather port in the far east Pacific and the long haul through the narrow passages from the Sea of Azov into the Mediterranean. We know Russia has been invaded by Napoleon and Hitler, with Great Loss to the Populous. It is understandable Russia is quite cautious at keeping their defense options open!
I don't give any quarter to Dictators for Life like Putin. However, We must look at the long term character of the Russian People and Nation.
One should not 'corner a bear, then begin poking it with a stick', as Obama is beginning to do!
We in the U.S. must remember that Moscow was Our Great Ally during WWII. We should always seek the best possible relationship between America and Russia! We must give each other the 'elbow-room' necessary.
The U.S. absolutely with our European Allies should consistently badger Russia to add Democratic Reforms; and accept monitored-fair referendum where first each province along the border in Ukraine, including Crimea (then those to the interior) can vote on joining Russia or staying Ukrainian! Simple majority rule.
We need to walk-back confrontation with our good ally Russia!