Final answer:
Voter turnout in the nineteenth century was high but began to decline in the twentieth, with differences in the North and South. The twentieth century saw further declines due to factors like wars, pandemics, and systemic electoral barriers.
Step-by-step explanation:
Comparing voter turnout in the twentieth century with that of the nineteenth century, we see significant changes, reflecting societal transformations and alterations in political engagement. During the nineteenth century, following a major shift in the United States, presidential election voter turnout rates were high, often reaching near 80%.
However, as we transitioned into the twentieth century, declining participation in elections became evident with turnout dipping to about 60% in the North by the 1920s and a dramatic decrease to around 20% in the South. This decline continued into the late twentieth and early twenty-first centuries, with the United States experiencing lower voter turnout compared to other OECD countries, attributed to factors such as lack of political salience and low social capital.
Over turnout trends within the twentieth century, external factors like World War I, the 1918 influenza pandemic, World War II, and the Vietnam War had adverse impacts on voter participation. Additionally, systemic issues such as laws inhibiting third-party candidates, the decline of political machines, and the rise of appointed officials over elected ones contributed to lower electoral engagement. Understanding these trends helps to contextualize the forces at play affecting voter turnout and political participation over time.