Let me know what you find. It’s possible the reference to his voting for Eisenhower in 1956 was mentioned in a book. Someone here on FR cited it, but I can’t recall the thread.
It would’ve made more sense as a left-winger (which he was) that he would be a committed Democrat (although he wasn’t old enough to vote in 1948, I can imagine his supporting pro-Soviet Communist Progressive Henry Wallace). He spent time at the far-left Highlander Folk School in Tennessee. One of the Communist goals to undermine the country was to manipulate the Black community and use them as a vehicle for their agenda vis a vis the Civil Rights movement (although they couldn’t care less for Black welfare, just as a useful tool).
Earlier in the 20th century, leftists/progressives wished to use the Eugenics movement (a la Margaret Sanger) to eradicate “undesirables” (which essentially consisted of all non-WASPs) and utilizing high-profile Black ministers into doing the work of “culling the herd” (via abortion/birth control).
When that didn’t turn out to be a serviceable notion, they took a different tack, and its results are impossible to ignore given the current state of our nation.
I saw plenty on the Eisenhower vote, many sources speculate with strength that he voted for him in 1956, he may have voted for his friend Nixon in 1960.
I was thinking about his letter in 1956, well he was only 27 when he wrote it, so he would only have had one presidential vote under his belt, with three left to go.