I still don't understand how Johnson only got 13% in Mississippi. Any Democrat is guaranteed a floor of around 42% without winning more than 10% of whites.
Blacks were essentially disenfranchised in MS (and for the most part in AL) until the Voting Rights Act of 1965 (and even then it wasn't until the late 1970s that Blacks voted at near normal rates). Johnson probably won around 10% of the White vote, ranging from the 34.5% he won in Itawamba County (which was just 6.8% Black) to < 5% in many Black belt counties were Blacks were disenfranchised. In Jefferson County for example Johnson won 5% and 4 years later, Humphrey won 63%.
