Maybe it was just East Texas, but Vidor especially was full of KKK and they were democrats.
I just responded because of the term “most”. It’s quite an exaggeration to say most democrats in Texas during the 1960s were in the KKK.
After all there were reportedly about 40,000 KKK throughout the U.S. in the mid 1960s and the population of Texas then was roughly 10 million.