More than a third of self-identified Republican primary voters said in a new INSIDER poll that they supported the racist chant at President Donald Trump's North Carolina rally last month.

The poll mirrored a partisan divide when it comes to racial attitudes.

About 38% of self-identified Republican respondents either somewhat approved, approved, or strongly approved of the "send her back" chant referring to a naturalized US citizen serving in Congress.

But only 5% of self-identified Democratic primary voters expressed similar attitudes.

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More than a third of self-identified Republican primary voters said in a new INSIDER poll that they supported the racist chant at President Donald Trump's North Carolina rally last month.

The poll mirrored a clear partisan divide when it comes to racial attitudes. About 38% of self-identified Republican respondents either somewhat approved, approved, or strongly approved of the chant. But only 5% of self-identified Democratic primary voters expressed similar attitudes, and they overwhelmingly disapproved of the crowd's chanting.

At the rally on July 17, Trump's supporters chanted "send her back" in reference to Rep. Ilhan Omar, a Somali-born Minnesota congresswoman who is a US citizen. She was one of four Democratic lawmakers of color that Trump had targeted in a series of racist tweets a few days before, telling them to "go back" and "help fix the totally broken and crime infested" countries "from which they came."

Omar was born in Somalia, while the other three lawmakers — Reps. Alexandria Ocasio-Cortez, Rashida Tlaib, and Ayanna Pressley — were born in the US.

Trump briefly tried to distance himself from the crowd's behavior but later embraced it and lauded them as "incredible patriots."

As with Trump's inflammatory tweets, the chant plays on racist tropes about deporting black Americans who are critical of the US.

Read more: Trump says supporters who chanted 'send her back' are 'incredible patriots' just a day after disavowing the chants

INSIDER asked over 1,100 people about their views on the "send her back" chant. Of those, 962 provided an answer to the question "Do you approve or disapprove of the crowd chanting 'send her back' in this clip?" They were invited to watch a brief clip of the chant.

About 64% of the respondents strongly disapproved, disapproved, or somewhat disapproved of the chant; 11% neither approved nor disapproved; 17% expressed some form of approval; and 7% said they didn't know how they felt about it.

While a larger share of Republicans said they approved of the chant, the INSIDER poll also found that:

36% of them either somewhat disapproved, disapproved, or strongly disapproved of supporters' racist chant.

About 19% neither approved nor disapproved, higher than the portion of self-identified Democrats who said they felt neutral about the chant.

7% said they didn't know how to respond.

Among self-identified Democratic primary voters, about 78% — the highest share — said they strongly disapproved of the crowd chanting "send her back." Only 4% said they were neutral on the chant.

Still, among Republicans, the political cost for Trump of employing such fiery attacks is considerably less. And his presidency so far has sought to entrench their support rather than broaden it.

In another recent INSIDER poll, 31% of self-identified Republican respondents didn't express an opinion on whether a lawmaker should disavow racist behavior from their supporters, and 15% said they generally disagreed with the question — making up almost half of such respondents.

Read more: Fewer than half of Republican voters say politicians should disavow racism from their supporters

While Trump has continued to say he isn't racist, his barrage of attacks against lawmakers of color continued over the past week. He criticized Democratic Rep. Elijah Cummings and called his majority-black district of Baltimore a "disgusting, rat and rodent infested mess" where "no human being would want to live."

Trump's advisers have reportedly concluded that his anti-immigrant rhetoric and policies are resonating among the white working-class voters who form a key part of his base. And though Trump's edge in the Electoral College may be larger next year than in 2016, a recent New York Times polling analysis found, the effectiveness of such attacks in galvanizing white-working class voters to turn out and vote is unclear.

But a no-holds-barred campaign rooted in racial resentment and a hardline immigration stance re-creates the dynamics of his last campaign — giving Trump a decent chance of keeping the White House in 2020.

SurveyMonkey Audience polls from a national sample balanced by census data of age and gender. Respondents are incentivized to complete surveys through charitable contributions. Generally speaking, digital polling tends to skew toward people with access to the internet. SurveyMonkey Audience doesn't try to weight its sample based on race or income. Total 1,184 respondents collected from July 19 to 20, 2019, a margin of error plus or minus 3.01 percentage points with a 95% confidence level.