In a memoir by Algis Budrys in Worlds of If, A Retrospective Anthology, he writes
I remember-unfortunately not in detail-a short story in which a returning white astronaut finds the US firmly in the hands of blacks. The blacks were depicted as rather middle-class types, given to three-piece suits and lip-service liberalism, which made their ineradicable basic antiwhite racial bias all the more poignant. The whites were called "sharkies" – this was long before the common use of "honky"…
He goes on to say that it appeared in Worlds of If in the early 1950s.
My searches have failed to turn up the story. Can anyone ID it?