http://www.danielpipes.org/13678/jfk-assassination
...Second, Kennedy's assassination profoundly impaired American liberalism. James Piereson's 2007 book Camelot and the Cultural Revolution (Encounter) establishes how liberals could not cope with the fact that Lee Harvey Oswald, a communist, murdered Kennedy to protect Fidel Castro's control of Cuba. Kennedy died for his anti-communism; but this wildly contradicted the liberals' narrative, so they denied this fact and insisted on presenting Kennedy as a victim of the radical Right, reading Oswald out of the picture.
Piereson ascribes much of American liberalism's turn toward anti-American pessimism to this "denial or disregard" of Oswald's obvious role in the assassination. "The reformist emphasis of American liberalism, which had been pragmatic and forward-looking, was overtaken by a spirit of national self-condemnation." Blaming American culture writ large for Kennedy's demise changed liberalism's focus from economics to cultural equity (racism, feminism, sexual freedom, gay rights) and that led them to identify with the countercultural movement of the late 1960s. The result was what Piereson calls a "residue of ambivalence" toward the worth of traditional American values.
Liberals remain trapped by this distortion, as manifested by, for example, Michelle Obama's 2008 remark that with her husband's ascent, "For the first time in my adult life, I am proud of my country," or by a New York Times article this week that blamed Dallas conservatives, rather than a hard-Left drifter, for the JFK assassination.