So I happened to stumble upon this graph of American voter turnout since 1824. And there are some noticeable and significant changes in voter turnout throughout history. I looked up timelines of voter policy and there doesn't seem to be any obvious correlations between the policies and the graph. So I'm curious, what outside factor caused these trends?
The drop that occurred during the 1920 election can be explained (at least partially) by the passage of the 19th amendment (women's right to vote). While the percentage of the population casting votes is lower in 1920, far more actual votes were cast than in the election of 1916 (~25 vs 17.5 million).
