"The North Atlantic Treaty Organization's (NATO's) 2016 summit was held in Warsaw, Poland, on July 8-9, 2016. The summit was the second meeting of the alliance's 28 heads of state and government since 2014, when Russia annexed Crimea and began providing large-scale military support to separatist forces fighting in Ukraine. Russia's actions in Ukraine and Eastern Europe more broadly have upended NATO's post-Cold War transformation from a military alliance focused solely on deterring Russia to a globally oriented security organization. Over the last two years, NATO has taken major steps to strengthen once again its territorial defense capabilities and to deter Russia. NATO's renewed focus on collective defense and deterrence has created some tensions within the alliance, particularly between those member states more sensitive to the Russian threat- especially in Eastern Europe-and those, such as Germany, with a long history of close ties to Russia. In addition, heightened fears about instability in the Middle East and North Africa have caused strain between those allies more concerned about security threats from NATO's south and those that continue to prioritize deterring and managing Russia."
CRS Report for Congress, R44550
Federation of American Scientists: http://www.fas.org/sgp/crs/index.html