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The deep dive: Who supports Donald Trump?

One of the larger unanswered questions in the race for the Republican nomination is who supports the current front-runner, Donald Trump?

One of the larger unanswered questions in the race for the Republican nomination is who supports the current front-runner, Donald Trump? 

While it is clearly too early to think political polls have any predictive power in saying who the eventual nominee will be, they do provide some information about name recognition, and they also likely matter for convincing donors and party elites of the viability of the various candidates. So, while we would be hesitant to argue that these early polls say much of anything about his chance for winning the eventual nomination, probing deeper reveals what types of voters find Trump appealing and where they stand on a number of issues.

RELATED: A rough summer for onetime GOP front-runners

The typical problem in using polls to explore differences among voters supporting competing candidates is that we usually do not have enough respondents to do this type of analysis responsibly. Most national polls at this point in the election cycle typically report findings based on 300 to 400 respondents who would vote in a Republican or Democratic primary. Focusing on supporters of particular candidates within these groups is therefore nearly impossible – even if a particular candidate is getting 50% of the vote, that would provide a look at only 150 to 200 respondents, too small a sample to responsibly report out certain characteristics, such as income or educational level. NBC News conducted two large-scale online polls with SurveyMonkey -- interviewing nearly 12,000 registered voters in July and August. The large sample size of these polls allows for a deep dive on two burning questions: Which Republican voters support Trump, and did his base of support change because of the first Republican debate?

In the wake of this month’s Republican debate, some political observers predicted that Trump’s controversial comments would alienate his followers and end his presidential run. Recent NBC News online surveys conducted by SurveyMonkey, however, show that Trump’s base did not change after the debate. We think much of this stability has to do with how Trump supporters differ from other Republicans. In general, Trump supporters are more conservative on a number of issues than supporters of other Republican candidates, and hold the most conservative position on immigration. But they are also less religious, and less likely to favor candidates who want to create stricter regulations on abortion.

Trump support:  Did the debate matter? 

By nearly any measure, those who supported the real estate magnate prior to the debate look a lot like those who favor him in the days following the debate. With an average confidence interval of roughly plus or minus 3 percentage points in both surveys, post-debate Trump supporters are nearly identical to pre-debate Trump supporters in terms of their levels of education, income, political ideology, religiosity and age. The only real difference is that Trump’s base post-debate was slightly whiter than it was prior to the debate (by about 8 percentage points), but even this change may be more of a result of differences in the survey’s sample rather than a real demographic shift. Most notably, despite the attention paid to Trump’s comments concerning women, there is no evidence of any erosion of support among female supporters of Trump – 42% of his support came from Republican women, compared to 39% before the debate.

Pre-debate Trump supporters
Post-debate Trump supporters
Female 39% 42% +3
High school degree or less 44% 43% -1
Age: 18-24 7% 5% -2
Age: 65+ 24% 23% -1
Under $50k 29% 33% +4
$100k+ 28% 28% 0
White 83% 91% +8
Self-identified "very conservative" 18% 19% -1
Evangelical 36% 38% +2
Religious attendance - at least once/week 34% 30% -4
Sample size (N) 607 (unweighted) 325 (unweighted)

The reason why the makeup of Trump’s base has remained unchanged may have to do with the ways in which Trump supporters differ from other Republicans and independents who lean Republican. Combining both datasets, we found that Trump supporters match non-Trump Republicans in terms of age, income, racial identity and political ideology, but there are some important differences. On average, those who favor Trump appear to be slightly less educated than Republicans who prefer other candidates (by an average of 9 percentage points). More notably, Trump supporters stand out from other Republicans on matters of religion. They are 9 percentage points less likely to consider themselves “born again” or evangelical Christians. They are also significantly less likely than other Republicans (by a margin of 14 percentage points) to attend church or another religious service on a weekly basis.

The biggest differences between Trump supporters and other Republicans, however, can be found in their views on public policy issues. Each survey asked respondents a series of questions about their positions on several matters of political debate. The table below compares the percentage of Trump and non-Trump Republicans agreeing with each statement.    

Non-Trump Republicans
Trump Republicans
Immigrants today are a burden on our country because they take our jobs, housing, and health care 61% 83% +21
Confederate flag is a symbol of Southern pride 79% 88% +9
Gun owner 44% 52% +9
The government should promote traditional values in our society
62% 70% +7
Blacks who can't get ahead in this country are mostly responsible for
their own condition
86% 93% +7
Increases in Earth's temperature are due more to natural changes in the environment 59% 65% +6
Government regulation of businesses usually does more harm than good 79% 83% +4
Display American flag 76% 80% +3
In today's economy, everyone has a fair chance to get ahead in the long
60% 55% -4
More likely to vote for a candidate who wants stricter limits on abortion* 60% 45% -15
Sample size (N) 3,719

*Asked in the post-debate survey conducted Aug. 7-10 among 3,991 Republican voters including 325 Trump supporters.

Trump Republicans are more conservative than other Republicans on almost every issue: Trump supporters are more likely to support the Confederate flag, own a gun, think the government should support traditional values and believe that black Americans who can’t get ahead in society are personally responsible for their own condition. But the biggest differences between Trump and non-Trump Republicans relate to their views of immigrants and their preferences for pro-life candidates. More than eight in 10 Trump Republicans view immigrants as a burden, compared to about six in 10 non-Trump Republicans. Given Trump’s repeated emphasis and far-right position on immigration, it is not surprising that so many of his supporters differ from other Republicans on the topic.

Perhaps just as interestingly, Trump Republicans do not seem to prioritize abortion issues as much as supporters of other candidates. Supporters of Trump were 15 percentage points less likely than other Republicans to say that they would be more likely to support a candidate who favors stricter limits on abortion. This does not necessarily mean, however, that Trump supporters are less pro-life than other Republicans, but rather that their views on abortion do not wholly determine their choice of candidate. In fact, 40% of Trump supporters said that a candidate’s stance on abortion would not make much difference to their vote compared to only 28% of supporters of other candidates. This may provide some insight as to why they continue to support Trump despite his flip-flopping on the issue.

RELATED: Donald Trump unveils immigration plans

Knowing how Trump backers differ from supporters of other Republican candidates provides some insight as to why he maintains a lead, despite what many pundits declared was a poor debate performance. During the debate, Trump stuck to positions that would not give his followers reason to stray. He doubled down on his stance on immigration, and did not espouse a position on abortion. Even though he has since come under fire for his treatment of gender issues during the debate, he did not lose female supporters afterward. If he loses his position at the top of the leader board in the following weeks, it seems unlikely to be a result of a changing base of support, but rather because of the ability of the other candidates to woo current Trump supporters.

The NBC News online surveys were conducted by SurveyMonkey from July 20-26, 2015 and August 7-10, 2015 among national samples of adults aged 18 and over. Respondents for this non-probability survey were selected from the nearly three million people who take surveys on the SurveyMonkey platform each day.

A full description of our methodology and error estimates for each survey can be found here.

The survey was produced by the Analytics Unit of NBC News in conjunction with Penn’s Program on Opinion Research and Election Studies with data collection and tabulation conducted by SurveyMonkey.