A slate of Democrats running for president defended fellow White House contender Sen. Kamala Harris Kamala HarrisHundreds of lawyers from nation's oldest African American sorority join effort to fight voter suppression Biden picks up endorsement from progressive climate group 350 Action 3 reasons why Biden is misreading the politics of court packing MORE (D-Calif.) after right-wing personalities and bots amplified conspiracies about her.

Apparent online bots promoted theories on social media after Thursday’s primary debate falsely claiming that the California Democrat, who is of Indian and Jamaican descent, is not black and is not a U.S. citizen.

“The attacks against @KamalaHarris are racist and ugly. We all have an obligation to speak out and say so. And it’s within the power and obligation of tech companies to stop these vile lies dead in their tracks,” Sen. Elizabeth Warren Elizabeth WarrenHillicon Valley: Subpoenas for Facebook, Google and Twitter on the cards | Wray rebuffs mail-in voting conspiracies | Reps. raise mass surveillance concerns On The Money: Anxious Democrats push for vote on COVID-19 aid | Pelosi, Mnuchin ready to restart talks | Weekly jobless claims increase | Senate treads close to shutdown deadline Democratic senators ask inspector general to investigate IRS use of location tracking service MORE (D-Mass.) tweeted.

The attacks against @KamalaHarris are racist and ugly. We all have an obligation to speak out and say so. And it’s within the power and obligation of tech companies to stop these vile lies dead in their tracks. — Elizabeth Warren (@ewarren) June 29, 2019

“The coordinated smear campaign on Senator @KamalaHarris is racist and vile. The Trump family is peddling birtherism again and it’s incumbent on all of us to speak out against it,” Washington Gov. Jay Inslee Jay Robert InsleeBarr asked prosecutors to explore charging Seattle mayor over protest zone: report Bottom line Oregon senator says Trump's blame on 'forest management' for wildfires is 'just a big and devastating lie' MORE (D) said, referring to the conspiracy theory that former President Obama was not born in the U.S.

The coordinated smear campaign on Senator @KamalaHarris is racist and vile. The Trump family is peddling birtherism again and it’s incumbent on all of us to speak out against it. — Jay Inslee (@JayInslee) June 29, 2019

Former vice president Joe Biden Joe BidenPelosi slams Trump executive order on pre-existing conditions: It 'isn't worth the paper it's signed on' Hillicon Valley: Subpoenas for Facebook, Google and Twitter on the cards | Wray rebuffs mail-in voting conspiracies | Reps. raise mass surveillance concerns Fox News poll: Biden ahead of Trump in Nevada, Pennsylvania and Ohio MORE, who had a contentious exchange with Harris during Thursday's debate, also likened the smears against Harris to the "birther" theories against Obama.

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"The same forces of hatred rooted in 'birtherism' that questioned @BarackObama's American citizenship, and even his racial identity, are now being used against Senator @KamalaHarris. It’s disgusting and we have to call it out when we see it. Racism has no place in America," he tweeted.

The same forces of hatred rooted in 'birtherism' that questioned @BarackObama's American citizenship, and even his racial identity, are now being used against Senator @KamalaHarris. It’s disgusting and we have to call it out when we see it. Racism has no place in America. — Joe Biden (@JoeBiden) June 29, 2019

“There's a long history of black Americans being told they don't belong—and millions are kept down and shut out to this day. @KamalaHarris is an American. Period. And all of us must call out attempts to question her identity for what they are: racist,” former Rep. Beto O’Rourke (D-Texas) tweeted.

“The attack on @KamalaHarris is racist and we can't allow it to go unchecked. We have a responsibility to call out this birtherism and the continued spread of misinformation,” Rep. Tim Ryan Timothy (Tim) RyanNow's the time to make 'Social Emotional Learning' a national priority Mourners gather outside Supreme Court after passing of Ruth Bader Ginsburg Lincoln Project hits Trump for criticizing Goodyear, 'an American company' MORE (D-Ohio) said.

The attack on @KamalaHarris is racist and we can't allow it to go unchecked. We have a responsibility to call out this birtherism and the continued spread of misinformation. — Tim Ryan (@TimRyan) June 29, 2019

“.@KamalaHarris doesn’t have shit to prove,” Sen. Cory Booker Cory Anthony Booker3 reasons why Biden is misreading the politics of court packing Bipartisan praise pours in after Ginsburg's death DHS opens probe into allegations at Georgia ICE facility MORE (D-N.J.), one of only three black candidates in the presidential race, tweeted.

Sen. Amy Klobuchar Amy Klobuchar3 reasons why Biden is misreading the politics of court packing Social media platforms put muscle into National Voter Registration Day Battle lines drawn on precedent in Supreme Court fight MORE (D-Minn.), who in the senate has sought to curb the influence of Russia on social media, said "We are better than this (Russia is not) and stand united against this vile behavior."

These troll-fueled racist attacks on Senator @KamalaHarris are unacceptable. We are better than this (Russia is not) and stand united against this type of vile behavior. — Amy Klobuchar (@amyklobuchar) June 29, 2019

South Bend Mayor Pete Buttigieg Pete ButtigiegBillionaire who donated to Trump in 2016 donates to Biden The Hill's Morning Report - Sponsored by Facebook - GOP closes ranks to fill SCOTUS vacancy by November Buttigieg stands in as Pence for Harris's debate practice MORE said Harris' presence in the race made for a better campaign.

"The presidential competitive field is stronger because Kamala Harris has been powerfully voicing her Black American experience. Her first-generation story embodies the American dream. It’s long past time to end these racist, birther-style attacks," he tweeted.

The presidential competitive field is stronger because Kamala Harris has been powerfully voicing her Black American experience. Her first-generation story embodies the American dream. It’s long past time to end these racist, birther-style attacks. https://t.co/x5Wdx8DKr8 — Pete Buttigieg (@PeteButtigieg) June 29, 2019

"This is racism. It was wrong before, and it’s wrong now. We won’t allow it again," Sen. Kirsten Gillibrand Kirsten GillibrandSunday shows preview: Justice Ginsburg dies, sparking partisan battle over vacancy before election Suburban moms are going to decide the 2020 election Jon Stewart urges Congress to help veterans exposed to burn pits MORE (D-N.Y.) tweeted.

This is racism. It was wrong before, and it’s wrong now. We won’t allow it again. https://t.co/MCkHFdronw — Kirsten Gillibrand (@SenGillibrand) June 29, 2019

The conspiracy theories were mainly promoted by fringe personalities popular in far-right circles. But one about Harris not being black was boosted by Donald Trump Donald John TrumpSteele Dossier sub-source was subject of FBI counterintelligence probe Pelosi slams Trump executive order on pre-existing conditions: It 'isn't worth the paper it's signed on' Trump 'no longer angry' at Romney because of Supreme Court stance MORE Jr., who retweeted one such message before taking the post down.

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“A lot of suspect accounts are pushing the 'Kamala Harris is not Black' narrative tonight. It’s everywhere and it has all the signs of being a coordinated/artificial operation,” social media researcher Caroline Orr tweeted after the debate.

A lot of suspect accounts are pushing the “Kamala Harris is not Black” narrative tonight. It’s everywhere and it has all the signs of being a coordinated/artificial operation. #DemDebate2 pic.twitter.com/DTeB2qWJnm — Caroline Orr (@RVAwonk) June 28, 2019

The Democratic primary race has gotten personal in the days leading up to this week’s debate, but all candidates have sought to prove themselves particularly attuned to race as they court an increasingly diverse base.