Shifting Tides in the Battleground States

The Future Painted in Blues and Reds

“Blue Fluid Acrylic Painting” by markchadwickart is licensed under CC BY-NC-ND 2.0

The Myth of Political Momentum

Political momentum is one of those handy terms overused and poorly defined by the media. Typically, it refers to short-term momentum, actions happening in the present tense, measured through political polls. Candidates are tracked day by day, minute by minute, with the hope of creating predictive models of success based on snapshots in time.

Are All Politics Local?

Measuring long-terms trends is all well and good, but to quote former Speaker of the House Tip O’Neill, “all politics is local.” Or is it? Andrew Gelman, writing for FiveThirtyEight nearly 10 years ago, refuted O’Neill’s adage, saying, “elections in the United States have become increasingly nationalized in recent decades…the decline is gradual, but we’re clearly at a lower level of variation now than we were 30 years ago…the red-blue map is much more stable from election to election than it used to be.”

Political Slope Analysis

I decided to measure this variation over time and space using Political Slope Analysis (my own term) to create a geographic map of party trends county by county. By measuring the mean and slope of the percentage of Democratic and Republican votes, I was able to get a birds-eye view of both general political attitudes and long-term shifts.

  • Average percentage points for all the elections between 2000 and 2016
  • Slope of the linear regression line of both Democratic and Republican votes across the 16-year period, (normalized by dividing by 0.0625, the maximum possible slope value)

Battleground States

POLITICO identified eight states as critical battlegrounds for the 2020 presidential election: Arizona, Florida, Georgia, Michigan, Minnesota, North Carolina, Pennsylvania, and Wisconsin. These states were selected based on polling, demography, past and recent election history, voter registration, interviews with party officials, and polls.

Arizona (Full-Sized Map)

  • Average percentage points R+7.6%
  • Democratic Slope 0.0%
  • Republican Slope -2.8%

Florida (Full-Sized Map)

  • Average percentage points 0.5% (R)
  • Democratic Slope 0.4%
  • Republican Slope -1.0%

Georgia (Full-Sized Map)

  • Average percentage points 9.3% (R)
  • Democratic slope 3.8%
  • Republican slope -5.0%

Michigan (Full-Sized Map)

  • Average percentage points 6.9% (D)
  • Democratic slope -2.0%
  • Republican slope -0.2%

Minnesota (Full-Sized Map)

  • Average percentage points 5.1% (D)
  • Democratic slope -0.5%
  • Republican slope -1.5%

North Carolina (Full-Sized Map)

  • Average percentage points 6.1% (R)
  • Democratic slope 4.3%
  • Republican slope -7.2%

Pennsylvania (Full-Sized Map)

  • Average percentage points 4.3% (D)
  • Democratic slope -1.8%
  • Republican slope 1%

Wisconsin (Full-Sized Map)

  • Average percentage points 4.1% (D)
  • Democratic slope 0.1%
  • Republican slope -1.7%


Political Slope Analysis provides a methodology for mapping out long-term trends in the political landscape. By comparing population maps with voter statistics, campaigns can direct resources to high-profile areas more likely to flip political persuasion. It’s a long game to be sure, but the best politics always are.

Medical Science Liaison in the pharma industry. Former technical writer, science writer, and market research analyst. General data enthusiast.

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