Russia annexes Crimea, NATO activates largest reinforcement since Cold War

Russian forces without insignia seized the Crimean Peninsula in late February 2014, and President Vladimir Putin signed a treaty annexing Crimea on March 18 after a disputed referendum. NATO suspended all practical cooperation with Russia and activated its Readiness Action Plan, the largest reinforcement of collective defense since the Cold War. President Obama imposed sanctions and deployed additional U.S. forces to NATO allies in Eastern Europe.