In the real era of racism, which was the early part of the 20th century, this was absolutely true. I checked Leip's tabulation of presidential elections and the Democratic vote for President in 1932 and 1936 in SC was over 98%. You couldn't find a Republican voter with an electron microscope. When it comes to racism, the 'Rats are knee deep in it.
“and the Democratic vote for President in 1932 and 1936 in SC was over 98%. “
Jim Crow, poll taxes, grandfather clauses, etc., were all devices intended by Democrats to prevent blacks from voting for Republicans!