"The Great Tax Wars" by Steven R. Weisman is about the debate about taxes during the progressive era. On p 123 [1] we read
“Since 1860, federal taxation had increased sixfold, yet the tax burden was primarily borne by the poor. At the same time, corporate profits had increased tenfold, much of it untaxed. It cost rich Americans 8 to 10 percent of their earnings to finance the government, while the poor paid taxes equivalent to 75 to 80 percent of their savings.”
Sounds very much like today: those with capital (like me) are benefiting from a low tax rate, while those who do have capital and earn their income from labor pay a higher percentage of their income as taxes. I definitely see the debates of the progressive era as being about capital.
[1] https://www.google.com/books/edition/The_Great_Tax_Wars/kw-Q...