The share of vote between Republicans and Democrats changes from one election to the next, sometimes with a small swing, sometimes with a massive shift. As we approach the 2016 Clinton/Trump contest this
map shows the pattern over time from 1916-2012 by State.
The map's basic structure uses a cartogram to depict the US as a series of equal-area regular shapes, each one giving equivalent visual priority. The time-series data is then displayed as a set of small multiple graphs providing a way of displaying a lot of data in the same visual display and which supports comparison from place to place.
Use the layers control to explore a few different graph types. Click the states to see the data.
There are two layers of popups. One supports the bar and line graph maps, the other supports the waffle grid and pie maps.
For consistency, colours are set as red for Republican and blue for Democrat despite these only becoming standard for the 2000 election and beyond.
Map by Kenneth Field (Esri Inc) using data from politico.com. Comments to
@kennethfield