Further to this post: I just became aware of a 2007 book by James Piereson called Camelot and the Cultural Revolution: How the Assassination of John F. Kennedy Shattered American Liberalism (Encounter Books).
Though I've not read the book, its thesis, as expressed in the subtitle, leaves me somewhat skeptical. To the extent that there was a "liberal consensus" on foreign and domestic policy in the '50s, the Vietnam War and the convulsions of 1968 had a lot more to do with "shattering" it than Kennedy's assassination, or so I'd be inclined to argue. (Don't forget that some of the greatest domestic triumphs of liberalism, such as the Voting Rights Act and Medicare, occurred during the Johnson administration. Not bad for a supposedly "shattered" movement.)