Growing political polarization, in one chart

Data source: MIT Election Data and Science Lab

In 2000, a slight majority (51%) of counties voting Republican were not close, with their candidate getting 60% or more of the total vote. By contrast, counties voting for the Democrat were typically much closer races, with only 22% of Democratic counties coming in at a margin of 60% or more for their candidate.

Twenty years later, political polarization has rendered much more of the map uncompetitive. Democrats have doubled their share of blowout win counties, from 22% of counties won in 2000 to 44% in 2020.

For Republicans, the shift is even more profound, from blowouts in half of counties they won in 2000 to four out of five they won in 2020. Republican presidential candidates earn more votes than Democrats in about 80% of all counties, and in 80% of those counties, the race is not even close.

Overall, uncompetitive races increased from 45% of all counties in 2000 to 75% in 2020. It’s a remarkable change in U.S. politics, and it only took about one generation.

The trend is also evident in counties flipping from one party to the other party. In presidential re-election years, a total of 221 counties flipped in 2004, and 226 flipped in 2012. In 2020, just 84 flipped, 69 for the Democrat, and 15 for the Republican.

You can define competitiveness in many different ways, but the title of most competitive might go to Pinellas County, Florida (Tampa metro area). It’s the only county to flip in four of the past five presidential elections. No county flipped in all five. In fact, 77% of counties have voted for the candidate representing the same party since 2000.

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