Story Highlights Top rationale for vote choice is opposition to other candidate

Many Clinton voters also cite her experience and qualifications

Trump voters are disproportionately issue-driven, want change

PRINCETON, N.J. -- The lead reason U.S. registered voters give for their choice of president in the 2016 election involves not liking something about the opposing candidate. All told, 28% of voters -- including equal proportions of Hillary Clinton and Donald Trump supporters -- cite reasons such as believing the other candidate is dishonest, unqualified or of poor temperament. The remaining voters offer more positive reasons for their choice of president, including their own candidate's qualifications (24%), policy stances (17%), personal qualities (14%) or party affiliation (9%).

Summary of Reasons Voters Support Hillary Clinton or Donald Trump In your own words, why are you most likely to vote for [Hillary Clinton/Donald Trump]? All voters Clinton voters Trump voters % % % Negative assessment of opponent 28 28 28 Qualifications/Experience 24 31 16 Issues/Policies 17 11 23 Personal qualities 14 13 15 Partisanship 9 12 6 Want change 4 <1 9 Other 2 2 2 No opinion 2 3 2 Based on U.S. registered voters who plan to vote for either Clinton or Trump Gallup, Sept. 14-18, 2016

These results are from a Sept. 14-18 Gallup survey in which self-identified U.S. registered voters were first asked whether they are voting for Democrat Hillary Clinton or Republican Donald Trump, and then asked to explain why in their own words.

In contrast to today, in 2008 -- the last presidential election without an incumbent seeking a second term -- hardly any respondents said the main reason they were supporting either Barack Obama or John McCain was that they objected to the opposing candidate. Many Obama supporters explained their vote in terms of wanting change from the current Republican administration, but not explicitly because they rejected McCain.

Similarly, in the 2000 election, another open-seat race, Gallup found relatively few voters basing their preference for George W. Bush or Al Gore on their objection to the opposing candidate.

The Anti-Vote for Clinton vs. Trump Is a Wash

As noted, 28% of both Clinton and Trump voters say they are backing that person because of something they don't like about the other candidate. Among the specific responses that make up this category, Trump voters are most likely to cite their lack of trust in Clinton. This is followed by their dislike of her, their determination to vote against her and their decision to vote for Trump as the "lesser of two evils."

Clinton voters are a bit more likely to give the "lesser of two evils" response, followed by saying that they dislike Trump and that he doesn't have the temperament to be president.

"Anti-Vote" Reasons Voters Support Hillary Clinton or Donald Trump All voters Clinton voters Trump voters % % % Negative assessment of opponent (Total) 28 28 28 Don't trust other candidate/Dishonest/Lack of integrity 6 2 10 Lesser of two evils 6 7 4 Do not like other candidate 4 5 4 Voting against other candidate 4 3 4 Other does not have temperament to be president 3 5 1 Do not favor other's agenda, ideas, platform 2 3 1 Other is not qualified to be president/Not a good candidate 2 3 1 Other has not done his/her job/Done a poor job 1 0 1 Other is too liberal <1 0 1 Based on U.S. registered voters who plan to vote for either Clinton or Trump Gallup, Sept. 14-18, 2016

Clinton Voters Drawn to Experience, Trump Voters to Issues

The perception that she has experience or is otherwise qualified to be president is the key reason 31% of Clinton voters give for backing her, nearly twice the percentage citing experience for Trump (16%). Clinton voters are also twice as likely as Trump voters, 12% vs. 6%, to say their candidate's party affiliation is the major factor in their decision. (See the full list of detailed responses in the "View complete question responses" document linked in the Survey Methods section.)

Meanwhile, Trump's voters (23%) are about twice as likely as Clinton's (11%) to cite agreement with their preferred candidate on issues or policy matters. (It should be noted that Gallup conducted this poll before the first presidential debate, for which viewers gave Clinton far more credit than Trump for having a good grasp of the issues.) For both candidates, most mentions in this category are general, rather than specific to individual policies.

Issue-Related Reasons Voters Support Hillary Clinton or Donald Trump All voters Clinton voters Trump voters % % % Issues/Policies (Total) 17 11 23 Favor his/her agenda, ideas, platform 10 9 12 Cares about poor, old, middle class, average person 1 2 1 Conservative policies 1 <1 2 Economic issues 1 0 2 Immigration issues 1 0 2 Defense/Military issues 1 0 1 Foreign policy issues 1 1 0 Reduce spending <1 0 1 Create jobs/Lower unemployment <1 0 1 Want less government/Reduce government <1 0 1 Healthcare issues <1 0 1 Based on U.S. registered voters who plan to vote for either Clinton or Trump Gallup, Sept. 14-18, 2016

Trump voters are also unique in naming "change" as a key reason for their vote choice, mentioned by 9% of his supporters compared with less than 1% of hers -- not surprising given that the current president is a Democrat.

Similar proportions of Clinton (13%) and Trump (15%) voters identify positive personal qualities about their own candidate as their primary motivation for backing that person. Among the specific responses falling into this category, 5% of Clinton voters say they "like her" and 3% say she has good morals or ethics. For Trump, 4% of his supporters cite his credibility or ability to keep promises, while 3% cite his leadership qualities and 2% simply say they like him.

Quality-Related Reasons Voters Support Hillary Clinton or Donald Trump All voters Clinton voters Trump voters % % % Personal qualities (Total) 14 13 15 Like him/her 3 5 2 Good morals, ethics, values 2 3 2 Credible/Reliable/Keeps promises 2 <1 4 Trustworthy/Honest/Integrity 2 1 3 Leadership qualities 2 1 3 Represents women/Favor woman for president 1 2 0 Based on U.S. registered voters who plan to vote for either Clinton or Trump Gallup, Sept. 14-18, 2016

Bottom Line

When voters are asked why they support Clinton or Trump in this election, the first reason nearly three in 10 give involves what they think is wrong with the opposing candidate. This is extraordinary when compared with recent open-seat elections, when few voters mentioned anything unflattering about the opponent as a reason for their vote. The current pattern does fit, however, with both candidates' lackluster favorable ratings thus far in 2016. Unusually high proportions of their own party members view both negatively -- 21% for Clinton and 31% for Trump in the latest Gallup Daily tracking figures. These disgruntled partisans may account for many of those who say they are voting for their preferred candidate as the "lesser of two evils."

Still, the majority of each candidate's voters do offer a positive reason for backing that person. Clinton's voters are about twice as likely as Trump's to cite their candidate's experience and qualifications to be president, while Trump's are twice as likely to cite policy positions. Additionally, Clinton has more people voting for her out of party loyalty, while Trump voters are more likely to say they expect him to be a change agent.

The upcoming presidential debates offer these candidates a final opportunity to boost their favorable ratings, display presidential gravitas and present ideas that appeal to swing voters. If after the third debate these improvements haven't materialized, even more voters may decide that the best reason to vote for one of the two is that he or she isn't the other.

Survey Methods

Results for this Gallup poll are based on telephone interviews conducted Sept. 14-18, 2016, with a random sample of 1,033 adults, aged 18 and older, living in all 50 U.S. states and the District of Columbia, including 931 registered voters. For results based on the total sample of registered voters, the margin of sampling error is ±4 percentage points at the 95% confidence level. For results based on the 444 registered voters who support either Hillary Clinton or the 407 registered voters who support Donald Trump, the margin of sampling error is ±6 percentage points at the 95% confidence level. All reported margins of sampling error include computed design effects for weighting.

Each sample of national adults includes a minimum quota of 60% cellphone respondents and 40% landline respondents, with additional minimum quotas by time zone within region. Landline and cellular telephone numbers are selected using random-digit-dial methods.

View complete question responses and results.

Learn more about how the Gallup Poll Social Series works.