Kamala Harris broke out from the other nine Democrats onstage during the second Democratic presidential primary debate on Thursday, calling on her personal experiences of racial injustice as a black woman.

“As the only black person on this stage, I would like to speak on the issue of race,” Harris said.

That’s when she was attacked on Twitter by a conservative provocateur for not being an “American black.” It’s a play straight out of the racist birther playbook used against Barack Obama when he ran for president a decade earlier. This time, though, those kinds of allegations don’t have to circulate for years on obscure right-wing forums before they reach a mainstream audience. On Thursday night, spammers and even one of President Trump’s sons spread the attack to millions of people within hours.

Harris, 54, was born in Oakland, California to a father from Jamaica and a mother from India. She spoke of her experience growing up black in the debate, recalling a story about neighbors who wouldn’t let their children play with Harris and her sister because of the color of their skin.

The attacks on Harris’s background started Thursday when Ali Alexander tweeted she is not an “American black.”

“She is half Indian and half Jamaican,” Alexander wrote. “I'm so sick of people robbing American Blacks (like myself) of our history. It's disgusting. Now using it for debate time at #DemDebate2? These are my people not her people. Freaking disgusting.”

Alexander’s claim was picked up by Donald Trump Jr., who tweeted it to his nearly 3.6 million followers.

“Is this true?” Trump Jr. wrote. “Wow.”

Trump Jr., who later deleted his tweet, wasn’t the only one using Alexander’s tweet to question Harris’s ethnicity.

Harris’s team denounced the comment as racist. “This is the same type of racist attacks his father used to attack Barack Obama. It didn’t work then and it won’t work now,” a Harris spokesperson told The Daily Beast.

More Twitter users copied and pasted Alexander’s message verbatim and tweeted it as their own, according to screenshots posted by writer Caroline Orr. Some of those accounts, like “@prebs_73,” have copy-pasted other popular right-wing tweets verbatim. Other accounts with right-wing references in their usernames and biographies piled on, accusing Harris of not being black.

“Ummmmm @KamalaHarris you are NOT BLACK. you are Indian and Jamaican,” wrote a Twitter user with a cross emoji, the word “CONSERVATIVE,” a red “X” emoji (a right-wing Twitter trope), and three stars (a QAnon symbol) in their username.

At least one known network of bot accounts was found spreading Alexander’s original tweet, BuzzFeed reported.

“ The conversation is, no matter who we are, our blackness should be challenged because what we look like is not ‘American enough.’ ” — Shireen Mitchell, Stop Online Violence Against Women

Shireen Mitchell, a technologist and founder of the group Stop Online Violence Against Women, said the accusation against Harris plays into a long-running debate that has been used to drive a white nationalist wedge through black communities.

“We are and have always been, for centuries in this country, having this little fight about who gets opportunities as black people and who doesn’t,” Mitchell said. “That includes colorism; that includes distinctions of where the ship actually landed; it includes if you are (and I am) a descendant of a slave who was born here versus a descendant of slavery from another country. Those distinctions, from my perspective, make no sense ever. But what it does is allow for white nationalist and nativist conversations to be planted in my community.”

A spokesman for Trump Jr. said Trump sent the tweet originally because he had not known that Harris’s mother was Indian.

“Don’s tweet was simply him asking if it’s true that Kamala Harris was half-Indian because it’s not something he had ever heard before and once he saw that folks were misconstruing the intent of his tweet he quickly deleted it,” the spokesman said.

Alexander, who describes himself as black and Arab, said that Harris has a “nasty, lying history with Black people.”

“Me pointing out that Kamala Harris has a mother from India and a father from Jamaica went viral last night because many people assume she descends from Black American Slaves,” he said in a statement to The Daily Beast. “She does not. I corrected Kamala Harris last night because she stole debate time under the premise that she is an African-American when she is in fact a biracial Indian-Jamaican who is a first generation American.”

This isn’t the first time pro-Trump activists have tried to undermine Harris and her authority to speak on issues of race based on her parents.

In January, right-wing operative Jacob Wohl, an associate of Alexander, argued on Twitter that Harris was ineligible to be president because her parents weren’t from the United States, even though she was born in California. Wohl’s claims were circulated by other right-wing figures online, in an attempt to create a birther-style question about whether Harris could legally run for president.

Mitchell, who has monitored harassment campaigns against black women since 2013, said Harris is facing a new, digital permutation of the birther conspiracy theory attacks President Trump levied against Obama.

“It’s a different iteration of birtherism: ‘where were you born?’ She was born in Oakland!” Mitchell said, referring to the conspiracy theory that falsely accused Obama of being born outside the U.S. “The conversation is, no matter who we are, our blackness should be challenged because what we look like is not ‘American enough.’”

Mitchell draws a distinction between two kinds of fraudulent accounts that try to discredit black people online. Botnets, an automated network of fake accounts, often tweet the same message. The technique allows a message to spread far and fast, with little effort. Some of the copy-paste accounts sharing Alexander’s message appear to be operated by real people.

Mitchell also monitors a trend called “marionetting,” in which someone will falsely pose as a black person online to push ideas that many black people might otherwise find objectionable.

Recent examples of marionetting include a troll who stole a black transgender activist’s picture to pose as a Trump supporter, and Russian-run accounts like “Blacktivist” that impersonated black Americans to sway black voters away from Hillary Clinton in 2016.

“I actually thought the botnet was going to die, because I felt like more marionetting was happening ... After this debate, I saw more botnets responding again, versus just marionetting.”

Fraudulent accounts often rely on stereotypes that trolls hope to apply to a collection of fake accounts, Mitchell said.

“The ‘black enough’ line has been a stereotypical frame,” she said.

“It has always been a systemic narrative. It’s just being expanded in this national debate”