The antipathy between the Louisiana crackers and the conservative New Orleans area residents ("Bourbons") was pronounced from the 1920s through the time of the Kingfish, to the time of WW2.
Long fought hard for the poor whites (crackers), building roads, charity hospitals and schools with free textbooks. His support of Louisiana State gave it dominance over the more patrician Tulane and built its Huey P. Long Medical Center.
His assasination in 1935 was followed for a time by a continuation of his policies, but the old conservatism eventually came back, not to be altered until the Civil Rights upheavel.
The lot of the Blacks improved under his regime; Long removed the poll tax requirement for voting (long before Texas and other southern states).
In other words, for a time, the goals of the crackers and blacks came closer together, although the idea of equality was still a long way off.

Look at some of the other songs on Randy Newman's web site to get a feel of the times.