You can learn a lot by studying the origins, conduct, and consequences of World War I (1914–18). And you can learn a lot by studying the origins, conduct, and consequences of World War II (1939–45). But to arrive at some approximation of definitive historical truth when it comes to 20th-century Europe, you need to think of those two events as the Thirty Years War of 1914–45. Only then is the connective tissue between the “Guns of August” and the horrors that were to befall Western civilization three decades later revealed.
Something similar applies to America’s wars in Vietnam and Afghanistan. In ways that may not be easily appreciated, the two are intimately related. Bringing to light their kinship—and, by extension, their true significance—requires situating them in a single historical framework. Classifying Vietnam as an episode in the Cold War and Afghanistan as an unrelated part of the Global War on Terror confers a certain superficial narrative order on the recent past. But doing so is like pretending that World War I and World War II were unrelated events. It overlooks essential connective tissue.
Instead, to identify a historical frame that encompasses both Vietnam and Afghanistan, consider this proposition: However momentous they were for Europeans, the events of 1989–91, when the Soviet Union imploded, left the American way of life all but untouched. True, the end of the Cold War had enormous implications for Western and Eastern Europe (soon to merge), for the states of the former Soviet Union (cut loose to pursue their own destinies), and for Russia itself (diminished and humiliated, but still a mammoth successor state to the USSR).
While these events unleashed a torrent of self-congratulation in the US, the passing of the Cold War did not substantively modify the aspirations or expectations of the American people. For decades, the United States had exerted itself to uphold and enhance the advantageous position it gained in 1945. Its tacit goal was not only to hold the communist world in check but to achieve ideological, economic, political, and military primacy on a global scale, with all but the most cynical American leaders genuinely persuaded that US supremacy served the interests of humankind.
Attach to this outlook whatever label you like: innocence, intractable ignorance, megalomania, naked imperialism, historical myopia, divine will, or destiny. Subsuming them, however, was the concept of American exceptionalism. Whatever your preferred term, here we come to the essence of the American project.