In three main ways, the JFK murder still has repercussions for Americans and the world. It also has a unique place in my life.
First, had the assassination attempt not succeeded, arguably neither the Vietnam War nor the Great Society expansion of government would have afflicted the United States as they did. The Virtual JFK: Vietnam If Kennedy Had Lived project concludes that "JFK would have continued to resist a US war in Vietnam. Even though the Saigon government, weak and corrupt, was destined for the dustbin of history, he would have resisted those calling on him to send US combat troops to Vietnam. He might have ended all military involvement."
As for government expansion, American historian Don Keko writes that Kennedy "lacked Lyndon Johnson's legislative abilities which would have doomed much of what became known as the Great Society. … Without the Great Society, the nation does not experience massive budget deficits and the economy would have been stronger."
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.