We could withdraw from NATO today and it would have zero impact on whether there's a future war in Western Europe (it's already failed in that regard in southern and eastern Europe namely former Yugoslavia and Ukraine). It's great that in the Cold War era that NATO might have (emphasis on the might have) prevented a war and created Pax Americana, there's no reason it's needed to sustain peace today in 2018. Europe isn't a bombed out shell from WW2 that needs a paternalistic U.S. with troops stationed across the continent to prevent the Germans starting the next great war. Europe doesn't need the U.S. to protect them against a Russia which they're perfectly capable of defending themselves against in the modern day and who wouldn't directly attack them anyway. The quote from the article "today, neither Europe nor the United States are wealthy or powerful enough, alone, to sustain and expand liberal democracy in a world increasingly dominated by China, Russia, and anarchy" is neither borne out by current events nor the trajectory of history. The governments of China and Russia aren't going to change into liberal democracies no matter whether NATO exists or not, nor will some random country like (insert developing world nation here) choose to vote for a pro-West government over a Hugo Chavez style socialist experiment because of NATO.