A passenger bus was attacked in eastern Ukraine as it traveled from Donetsk, the “capital” of the region controlled by Russian backed separatists. The attack could mean the end of a shaky cease-fire that was established last year between the Ukrainian government and the Russian backed separatists. The cease fire has been violated by both groups on numerous occassions. In the meantime, a peace summit on Ukraine that was to be held between Ukraine, Russia, France and Germany was canceled after foreign ministers were unable to come up with a plan of action. Matthew Rojansky, the director of the Kennan Institute at the Wilson Center, joins us to discuss the ongoing crisis in Ukraine.