"There's so much bitterness I thought they would get one of us, but Jack, after all he'd been through, never worried about it."
-Edwin Guthman, Justice Department spokesman who was with RFK on the afternoon of the JFK assassination.
Congressman Dan Flood of Pennsylvania was old-school, and a letter from the President on his birthday was the sort of thing it was savvy to send him: he liked attention from On High. Kennedy, about to leave on a political trip out west, took care to cover his eastern flank with this letter, and so signed and sent it to arrive with his "warmest congratulations" on Flood's birthday, November 26th - which would be, that awful year, the day after his own funeral.
Typed Letter Signed, as President, with one word autograph salutation, 1 page, quarto, The White House, November 26, 1963; to "Dan", being Congressman Dan Flood. Although dated November 26, Kennedy was as of that date, dead four days - and so this post-dated birthday message is extremely rare.