Those crisp simple chic and very American Bill Blass clothes on Gene Tierney totally modernized this film and Gene herself. She was the new JFK era, the Sixties incarnate and for me captured the whole ethos of the film.
The irony is that Tierney's ex-husband, Oleg Cassini, who had designed the clothes she wore in most of her movies in the 40s and early 50s, was by 1961 the chief designer for Jackie Kennedy and set much of her fashion tone.
Not to mention that, in the mid-40s, Tierney had had an affair with the young Jack Kennedy while she was still wed to Cassini. The only thing that stopped them from marrying was that Joseph P. Kennedy thought marriage to a divorcee would kill Jack's political career before it had even begun, plus the fact that Gene was a Republican. Politics -- and fashion -- do indeed make strange bedfellows!
In the book, the character of Lafe Smith was a Senator from Iowa. They changed his state to Rhode Island in the film, in part because Lawford's accent was acceptable for a Rhode Islander but not an Iowan, but also to emphasize his Kennedy connection. Politically, Rhode Island is in many ways a sort of mini-Massachusetts, and this too could only serve to emphasize the link between JFK and his brother-in-law. The only problem is that the name "Lafe" sounds too rustic, too middle-American, for the sort of East-Coast sophisticate Lawford was supposed to be playing.
Never heard that. I'm not sure whether that's what the book's Lafe's real name was (I tend to doubt it), but "Lafayette" could fit the Rhode Island/Lawford variation of the character in the film.