The days when anti-war agitation by radicals like Rosa Luxemburg, Karl Liebknecht, or, for that matter, Lenin resonated with millions of workers tired of being cannon fodder for their rulers are clearly long gone, and so is the period of turmoil around 1968, when rebellious GIs subverted America’s military adventure in Vietnam. A world order marked by imperial tensions ready to spill over into full-out war, however, is still very much with us, arguably more so than in recent decades.