Charles A. Beard,
Contemporary American History, 1877-1913
“ With the spread of direct elections and the initiative and referendum, and the adoption of the two amendments to the Federal Constitution authorizing an income tax [73] and the popular election of Senators, the milder demands of Populism were secured. At the same time, the prosperity of the farmers and the enormous rise in ground values which accompanied the economic advance of the country removed some of the most potent causes of the discontent on which Populism thrived. Organized Populism died a natural death. ”
