Tuesday, September 13, 2016

America Doesn't Swing Any More

The Guardian believes that politics in the United States has become so polarized that the number of swing states is becoming less and less. Historically a large number of states were likely to switch between Republican and Democratic presidential candidates from one election year to the next.

In 1980 Ronald Reagan won 44 of 50 states, with 17 states switching political allegiance since the previous election, swinging from Democrat to Republican. At the last election, in 2012, just 2 states voted differently to how they voted in 2008.

In Swing States: How Changes in the Political Landscape Benefit Trump the Guardian argues that the polarization of U.S. politics over recent years means that states are now less likely to switch between political parties from one election year to the next. They have visualized this trend with an interactive map and timeline.

The purpose of the Guardian's map is to visualize how the number of swing states has fallen over time. Which the interactive map does very effectively. The swing states for each year are shown using the visual metaphor of the state polygons actually spinning around and changing color. In other words the states actually swing on the map.

The number of states which have swung in each election year is shown using a simple stacked column chart placed on top of the dates. Reading the charts from right to left, in chronological order, it is easy to see at a glance that the Guardian's premise appears to be correct. Since 1964 the number of swing states in each election year has generally fallen.

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