Taking stock of history's longest-lasting alliance at ten-year intervals has been a regular but increasingly daunting exercise for scholars focusing on the North Atlantic Treaty Organization (NATO). The scope and pace of developments to be considered has multiplied since the Cold War days when U.S.-Soviet rivalry was paramount and seemed permanent. Whatever can be said today tends to get dated quickly. The Arab Spring intrudes, the Eurozone crisis happens, the War on Terror winds down, Russia's war in Ukraine drags on, Donald Trump comes and goes. Trying to explain why the alliance is still here and where it might be heading is a challenge, and the answers are bound to differ.
NATO after Sixty Years includes contributions originally prepared for a conference in 2009 (on the sixtieth anniversary of NATO's formation) but published three years later, during which time the international environment changed considerably. But because all but two of...