From a polling standpoint, Kamala was the overall winner of the first Democratic debate

AUTHOR’S NOTE: The author of this blog post is a supporter of Elizabeth Warren’s presidential campaign, but is not officially involved with the Warren campaign.


The pollster Morning Consult and Nate Silver’s predominantly election analysis and sports analysis-centric website FiveThirtyEight teamed up over the course of the two-night first Democratic presidential debate, held two days ago and yesterday, to poll likely Democratic primary or caucus participants in three waves: before the first night of the debate, between nights of the debate, and after the second night of the debate. Here’s the polling methodology information for each wave polled:

…The first wave of the poll was in the field from June 19 to June 26 among 7,150 registered voters who say they are likely to vote in their state’s Democratic primary or caucus. It has a margin of error of +/- 1 percentage point using the 2016 Democratic primary electorate as the true population.

The second wave of the poll was conducted from June 26 to June 27 among 2,041 respondents who previously responded to the first wave; it has a margin of error of +/- 2 percentage points. Of those respondents, 1,134 watched the first debate.

The third wave of the poll was conducted from June 27 to June 28 among 1,399 respondents who previously responded to the first wave, including 428 who responded to both the first and second waves; it has a margin of error of +/- 3 percentage points. Of those respondents, 97 watched the first debate, 89 watched the second debate and 757 watched both debates.

Source

Of the 25 candidates currently seeking the Democratic presidential nomination, 20 of them participated on one of the two nights of the debate. The left-most two columns below denote which candidates qualified for the debate and which candidates participated on which night, while the right-most column below denotes the candidates who failed to qualify for the debate and, thus, were not allowed to appear on either night.

First night (6/26)

  • Cory Booker
  • Julian Castro
  • Bill de Blasio
  • John Delaney
  • Tulsi Gabbard
  • Jay Inslee
  • Amy Klobuchar
  • Beto O’Rourke
  • Tim Ryan
  • Elizabeth Warren

Second night (6/27)

  • Michael Bennet
  • Joe Biden
  • Pete Buttigieg
  • Kirsten Gillibrand
  • Kamala Harris
  • John Hickenlooper
  • Bernie Sanders
  • Eric Swalwell
  • Marianne Williamson
  • Andrew Yang

Both nights of the debate were televised in English on most, if not all, NBC affiliates and on MSNBC, and in Spanish on Telemundo.

Did not qualify

  • Steve Bullock
  • Mike Gravel
  • Wayne Messam
  • Seth Moulton
  • Joe Sestak

Based on the polling data, there was a clear overall winner of the first debate: Kamala Harris, who participated in the second night of the debate. Kamala more than doubled her support as a result of her debate performance: 16.6% of respondents to the third wave of the poll stated that they support Kamala, representing a 10.3% increase from the second wave of the poll and an 8.7% net increase from the first wave of the poll. Based on the third wave of the poll, Kamala is now within the polling margin of error for second place with Bernie Sanders and Elizabeth Warren. Kamala’s debate performance included a memorable debate over segregation and school busing-related issues against Joe Biden, who also participated in the second night of the debate.

Joe Biden was, at least arguably, the overall loser of the first debate, although he remains the frontrunner for the Democratic nomination, at least for now. Biden lost nearly a quarter of his support as a result of the debate, falling from 41.5% before the first night to 35.4% between nights to 31.5% after the second night. Out of the 20 candidates who participated in the debate, only Biden saw a drop in his favorable rating, with Biden’s favorable rating falling from 76.5% to 75.6%, representing a drop in favorability of 0.9%.

Only two candidates saw a drop in their unfavorable rating: Bernie Sanders, who participated in the second night of the debate, and Elizabeth Warren, who participated in the first night of the debate. Warren saw the largest drop in her unfavorable rating, with her unfavorable rating falling 1.0% from 13.5% to 12.5%. Bernie saw a nominal drop in his unfavorable rating, with his unfavorable rating falling 0.1% from 17.6% to 17.5%.

Most candidates saw both their favorable rating and their unfavorable rating rise as Democratic voters got to learn about them and learn more about them. Candidates that saw a much larger increase in their favorable rating than their unfavorable rating include Julian Castro and Cory Booker, who participated in the first night of the debate, as well as Kamala, who participated in the second night of the debate. Candidates that saw a much larger increase in their unfavorable rating than their favorable rating include Beto O’Rourke, who participated in the first night of the debate, and Marianne Williamson, who participated in the second night of the debate.