NATO leaders are considering forming a rapid reaction force of 4,000 troops to counter Russian military action in Ukraine. In response, Russian leaders have said they will change their military doctrine to prepare for changing military threats, and Vladimir Putin has reportedly claimed he could conquer Kiev in a fortnight if he wanted to. We’ll talk with historian and security expert John Mearsheimer of the University of Chicago about the situation in Eastern Europe. His most recent books are ‘The Tragedy of Great Power Politics’ and ‘Why Leaders Lie: The Truth about Lying in International Politics.’ (photo: In this photo taken on Friday, Aug. 29, 2014, Russian President Vladimir Putin holds a terrestrial globe presented him as a gift in Tver region, Russia. (AP Photo/RIA-Novosti, Mikhail Klimentyev, Presidential Press Service))