Democratic presidential candidates are vying for votes, but banding together as race becomes a key issue in this campaign.

NBC's Rachel Scott is in Chicago, where several candidates are courting African American voters at the Rainbow Push Coalition convention and defending Senator Kamala Harris from a new attack on her background.

Rachel Good morning.

Good morning, Eva.

Senator Harris identifies as black.

She graduated from a historically black university and is a member of the first black Greek sorority.

But her racial identity is being called into question, and now the 2020 Democratic candidates are putting politics aside to back her up.

This morning, the pack of Democratic candidates united to defend one of their own after online attacks question the racial identity of Senator Kamala Harris.

One person tweeting.

Camilla Harris is not an American black.

She is half Indian and half Jamaican.

I'm so sick of people robbing American blacks like myself off our history.

Tweet!

Reportedly gaining attention after The New York Times reports Donald Trump Jr shared it later, deleting it part of the strength of our nation bees attacks on.

Harris claims she is not African American and that her ancestors didn't experience US slavery.

Harris, born to immigrant parents from Jamaica and India, identifies as black this controversy over her racial identity reminiscent of the birtherism debate, which falsely claimed President Obama was not born in the United States.

Harris, his campaign tells ABC News.

Those attacks didn't work then, and they won't work now Senator Elizabeth Warren, fresh off of making her pitch to a black church on the south side of Chicago, We are in a fight for the very soul of our nation, stepped in as the first candidate to defend Harris, calling the accusations racist and ugly.

Joe Biden labeled the attacks disgusting just after Hair challenged his civil rights record on the debate stage.

You also worked with them to oppose busing, an unlikely source cutting bite and some slack.

I think she was given too much credit for what you did wasn't that outstanding, and I think probably he was hit harder than he should have been hit.

But on back in South Bend, racial tensions prompted Mayor Pete Buddha judge to step off the trail after the fatal shooting of a black man by a white police officer, but a judge back in town for a peace walk on the same day as the funeral for that man, Eric Logan.

Well, this is my home.

But also these issues can't be separated.

The challenge we face here in South Bend is symptomatic of a national challenge, and Mayor Pete Buddha judge will be back on the campaign trail on Tuesday, stopping right here in Chicago to appear before Jesse Jackson's Rainbow Push Convention with Rachel Scott Forests in Chicago.

Thanks so much.

Hi, everyone.

George Stephanopoulos here.

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