In this book Tuchman takes a step beyond the traditional historian's story-telling role to provide color-commentary about a specific subset of examples of misgovernment that she classifies as "folly." Not all examples of misgovernment can be classified as folly as explained in the following quotation.
"Misgovernment is of four kinds, often in combination. They are: 1) tyranny or oppression ... , 2) excessive ambition ... , 3) incompetence or decadence ... , 4) folly or perversity. This books is concerned with the last in a specific manifestation; that is, the pursuit of policy contrary to the self-interest of the constituency or state involved. Self-interest is whatever conduces to the welfare or advantage of the body being governed; folly is a policy that in these terms is counter-productive."
Her definition of folly:
“To qualify as folly for this enquiry, the policy adopted must meet three criteria: It must have been perceived as counter-productive in its own time, not merely by hindsight. This is important because all policy is determined by the mores of its age...Secondly, a feasible alternative course of action must have been available. To remove the problem from personality, a third criterion must be that the policy in question should be that of a group, not an individual ruler, and should persist beyond any one political lifetime.”
The book then examines in detail four events from history that fit her criteria of folly; (1) Actions taken regarding the Trojan horse that led to the subsequent fall of Troy, (2) Actions taken by the Roman Catholic Papacy leading up to the Protestant Reformation, (3) Actions taken by the British government that lead to the American Revolutionary War, and (4) Decisions that led to American involvement in the Vietnam War. The Protestant Reformation and American Revolution are obviously significant turning points in world history. The fall of Troy is profound because it became a founding myth for Western Civilization. Inclusion of the Vietnam War in the book was a tilt toward commentary on a more recent example of folly, and is probably not all that significant in the long view of history. But the Vietnam War was fresh in the minds of readers when this book was first published in 1984, nine years after the fall of Saigon.
Implicit in Tuchman's definition of folly is the suggestion that if individuals in power at the time had been wiser the subsequent history could have played out in a peaceful manner. But my impression from the book is one of inevitability (or is it fate?) from the entangled politics of the times of each of the four historical events studied. It's interesting to note that people were present at the time of each event that anticipated and warned of needed reform or change in policy. But in each case the political inertia of the power structure was such to make heeding the warnings impossible.
Subsequent history supports the book's view regarding the folly of the Vietnam War. This book's review of U.S. involvement in the Vietnam War was a painful reminder for me of my own memories of living through that era in real life and real time. I see ominous parallels with current events in Afghanistan.