http://www.newrepublic.com/article/1...-and-what-next

Putin's War in Crimea Could Soon Spread to Eastern Ukraine And nobody—not the U.S., not NATO—can stop him

Vladimir Putin has asked the Federation Council—the upper chamber of Russia's dummy parliament—to authorize the use of force not just in Crimea, but "on Ukraine's territory until the socio-political situation is normalized." And though American spies and the Washington Post categorically ruled this out just days ago, this was not entirely unexpected. The situation is changing rapidly, but here are some initial thoughts.
Good read to understand Putin's mindset.