Part of the difficulty of picking winners and losers in a debate is that each voter brings a different rubric to the task. For example, a Democrat whose top priority is enacting stricter gun control may be looking for different things in a candidate’s performance than a voter whose sole objective is to get President Trump out of office. So to get a more nuanced picture of which candidates did well in last week’s third Democratic presidential debate, let’s break down reactions among these differently motivated voters.
To that end, our FiveThirtyEight/Ipsos poll, conducted using Ipsos’s KnowledgePanel, contacted the same set of respondents both before and after the debate and asked them what issue was most important in determining their vote in the primary. And by far, Democrats’ most common answer was the ability to defeat Trump — nearly 40 percent of respondents said this was their top issue. Health care, the economy, wealth and income inequality and climate change also ranked near the top of the list, though well behind a candidate’s ability to win.1 These priorities did not shift much after the debate either (all changes were within the poll’s 1.9-point margin of error).
A lot of Democrats really want to beat Trump
Share of respondents to the FiveThirtyEight/Ipsos poll who said that each issue is the most important to them, before and after the debate
Share for whom issue is most important | ||||
---|---|---|---|---|
issue | Pre-debate | Post-debate | ||
Ability to beat Donald Trump | 39.6% | 39.6% | ||
Health care | 9.9 | 11.0 | ||
The economy | 8.0 | 8.7 | ||
Wealth and income inequality | 7.9 | 8.4 | ||
Climate change | 7.4 | 6.5 | ||
Gun policy | 4.2 | 4.8 | ||
Immigration | 3.3 | 3.7 | ||
Something else | 3.3 | 3.5 | ||
Social Security | 3.4 | 3.2 | ||
Education | 2.5 | 2.4 | ||
Racism | 3.0 | 2.4 | ||
The makeup of the Supreme Court | 1.7 | 1.7 | ||
Taxes | 1.3 | 1.3 | ||
Jobs | 1.9 | 1.1 | ||
Foreign affairs | 1.3 | 0.7 | ||
Crime | 0.7 | 0.4 | ||
The military | 0.3 | 0.4 | ||
Sexism | 0.1 | 0.2 |
But although the issues voters prioritized didn’t change much, this question can tell us something else: whether voters’ priorities influence their views of the debate. Specifically, we can cross-reference which issues respondents said they cared about before the debate2 with how they graded each candidate’s performance afterward in order to answer the question of how each bloc of Democrats — climate-change Democrats, income-inequality Democrats, and so on — thought each candidate did.3
Take someone like Sen. Elizabeth Warren. She got the highest overall marks for her debate performance (respondents gave her an average score of 3.3 out of 4), but she got even higher scores from voters who prioritized climate change or defeating Trump (3.5 from both groups). Her strength with the latter group could be an especially positive sign for her because Democrats seem to care deeply about winning this year. (What’s more, the share of respondents in our poll who said they thought Warren could beat Trump ticked up slightly after her debate performance.)

But Warren wasn’t the only candidate to get high scores from voters who said the most important issue was beating Trump. Former Vice President Joe Biden was graded higher by that group (scoring a 3.1) than by the respondent pool as a whole (3.0), though both scores were less impressive than Warren’s. South Bend, Indiana, Mayor Pete Buttigieg and former Rep. Beto O’Rourke also scored well with voters who prioritize beating Trump — they were the next-best performers after Warren (3.3 and 3.2, respectively).
Warren didn’t just score well with voters whose top issue was climate change or beating Trump — she was judged the top performer across all five voter groups we looked at.4 Among voters who prioritized health care and wealth and income inequality, however, she was neck-and-neck with Sen. Bernie Sanders, who has made single-payer health care and the redistribution of wealth big parts of his campaign. And among climate-change voters, Buttigieg and O’Rourke were once again close behind Warren. Warren scored the best with economy voters, too, but of the five issues we looked at, economy-focused Democrats gave candidates worse marks across the board, suggesting that they were unsatisfied by what they heard in the debate.
Of course, voters may be inclined to overrate the debate performance of their favored candidates, and their No. 1 issue is often linked to which candidate they prefer. (For example, two-thirds of the voters who said electability was their top priority were considering a vote for Biden before the debate, and 58.0 percent of those who prioritized wealth and income inequality were considering voting for Sanders.) So to ascertain whether the debate actually changed the minds of Democrats who prioritize these five issues, let’s look at the pre- to post-debate changes in which candidates these respondents were considering voting for.

Again, this looks like good news for Warren — she picked up potential supporters among these five voter groups — and bad news for former Cabinet secretary Julián Castro and Sen. Kamala Harris, who lost potential supporters across most of these issue areas. The two biggest increases in potential support were Warren’s increase among respondents who prioritized the economy and O’Rourke’s uptick among respondents who prioritized climate change. In Warren’s case, the share of economy voters considering her before the debate was much lower (22.4 percent) than the share of voters considering her overall (44.4 percent), so the increase served to shore up her potential support among a subset of respondents with whom she had been unusually weak. O’Rourke, however, had been doing fine among climate voters before the debate (15.6 percent), so his increase meant he now has a lot of support among that group of voters (21.4 percent of climate voters are now considering him, compared with 16.1 percent of all voters in our poll).
Other notable changes include Biden’s improvement among health care voters — he improved by 3.9 points. That means 57.6 percent of that group is now considering him, which is substantially more potential support than any other candidate got among these voters (Warren and Sanders, who have the second- and third-most potential support, are in the low 40s). And the two biggest decreases both belong to Harris, who saw a decline in potential support among both electability and health care voters.
Harris’s decline among electability voters bodes especially poorly for her because so many likely Democratic primary voters prize the ability to beat Trump over all other issues, which means that this voter group seems particularly key to the candidates’ chances. Meanwhile, Warren’s increase among these voters, though not that large in absolute terms (2.4 percentage points), does mean that she is now being considered by 54.2 percent of these respondents, trailing only Biden at 68.4 percent.
However, Biden’s dominance of this category is key to his overall support, and many political observers believe he will remain the front-runner as long as he retains his aura of electability. And although Warren made gains in this category after the third debate, so did Biden. Voters who prioritize defeating Trump became more likely to consider voting for him, to the tune of 1.6 percentage points. That suggests that it will take more than a rambling answer on segregation and attacks on his age to convince Democrats that Biden can’t beat Trump.