There are two reasons to engage in counterfactual history. Greenfield prefers the more lenient label “alternate history.” One is to identify critical events, hinge points of history, and analyze why they turned out the way they did. To ask whether there would have been a Cold War if Franklin Roosevelt had lived to complete his fourth term is to conduct a thought experiment on the causes of the breakdown of the Grand Alliance of World War II. Were personal considerations crucial — was Harry Truman overly suspicious, perhaps? Or were larger factors decisive?
The key to the usefulness of such experiments is controlling for everything but one variable. This is impossible, of course, but approximations can nevertheless be revealing. The trouble is that the approximations attenuate as the experiment progresses, for fiddling with reality creates its own context. In Greenfield’s case, he can imagine, with some confidence, what Nov. 23, 1963, would have looked like whether Kennedy had lived or died the day before. But as to November 1964, or July 1965, or any other date after that, he is just guessing.
Yet guessing can be fun, which is the second reason to engage in counterfactualism. Historical fiction has a long lineage. Homer, Shakespeare and Dickens indulged, as did countless authors less distinguished. Greenfield amuses himself concocting a second inaugural gala at which the Beach Boys sing “Fun, Fun, Fun (in a Second Term With JFK)” and Roy Orbison croons “Oh, Pretty Woman” (“This one’s for you, Jackie,” he says). Kennedy brings the Beatles to the executive mansion and declares, “Not since the British burned the White House in 1812 has a foreign invader conquered our land as swiftly and thoroughly as have John, Paul, George, and Ringo.”
More seriously (to the extent fantasy can be serious), Greenfield’s Kennedy successfully resists broad pressure to escalate the war in Vietnam. This has been the touchstone of the Camelot claque since the 1960s: that Kennedy would have had the wisdom and strength to keep America out of the morass that Vietnam became. The argument is not implausible. The real Kennedy did hint at a basic review of U.S. policy in Southeast Asia. And if he had won a second term, his lame-duck status would have granted him a certain political freedom denied to presidents who have another race to run.
But it’s worth remembering that the American effort in Vietnam looked promising to most observers until very late in what would have been that second term. Of course, Greenfield’s Kennedy is blessed with the author’s hindsight. Real presidents aren’t so fortunate.