During the mid and late 1930’s a National Sales Tax was hotly debated. It was proposed by Republicans and conservative Democrats as a way of balancing the budget. It also had strong support from financier Andrew Mellon. Most Democrats, including FDR, were very opposed to it.
In 1934 the Mississippi Sheiks (Walter Vinson, Bo Chatam and Lonnie Chatam) voiced their opinion in this song.