I can think of people who would flip for most elections, but this one stumps me. Any ideas?
Bonus: Describe a Goldwater 64-Humphrey 68 voter
Extra Bonus: Describe an Al Smith 1928 Hoover 1932 voter
A conservative or Republican Catholic voter who supported Smith in 1928 because of their common religion, but returned to their normal partisan loyalties in 1932, despite the Depression. This could describe voters in Elk County, Pennsylvania. Elk County was won by Smith in 1928, due to its predominantly Catholic population, but Hoover gained several points there in 1932, even though he did much worse in Pennsylvania as a whole. It may also describe some voters in Boston or New York City, as Roosevelt didn't improve much upon Smith's margins with Catholics.
As for the Dewey-Stevenson voter, possibly a New Yorker who supported Dewey out of home-state solidarity, or more likely, a handful of rural voters in North Georgia (Dawson County, north of Atlanta, was the only Dewey county that Stevenson won in 1952).