Vice President Joe Biden speaks at the Atlantic Council's conference, in a special tribute to NATO and the European Union, Wednesday, April 30, 2014, in Washington. Biden drew parallels between Russia's interference in Ukraine and the world wars of the last century. Biden said Ukraine's struggles start with Russia's acute violation of rules that the 20th century taught us must be upheld. He says Russia has violated the fundamental principle that Europe's borders cannot be changed by military force. (AP Photo/Jose Luis Magana)