Landslide counties in presidential elections have increased by 283% since 1980

See Bellwether Counties Nearly Wiped Out by 2020 Election: All but one county that had chosen every presidential winner since 1980 went for President Trump this year; Washington state’s Clallam County is the lone survivor by John McCormick of The WSJ. Excerpts:

"America has become so polarized that presidential bellwether counties—those that consistently back the national winner, switching between parties in the process—are nearing extinction.

From 1980 through 2016, 19 of the nation’s more than 3,000 counties voted for the eventual president in every election. Only one of them, Washington state’s Clallam County, backed President-elect Joe Biden last week."

"Election results compiled by the Associated Press show only 2.5% of the nation’s counties flipped from one party in 2016 to the other in 2020. For most of those that did flip, it was by small margins.

In 1980, 391 counties were “landslide” territory: places where the presidential vote split was at least 20 percentage points more partisan than the nation overall. This year, more than half of all counties met that definition."

If we go from 391 to 1,500 (half of 3,000) we go up by  1,109. Then 1,109/391 = 2.83.

See also How Politics Has Pulled the Country in Different Directions: The 2020 election results are just the latest indicator of how Americans have been drifting apart for decades from The WSJ.