Transcript for Biden and Harris speak in first campaign event as reactions to VP pick pour in
This is a moment of real consequence for America. Everything we care about, it's all on the line. Reporter: This afternoon in Delaware, the official debut of the Joe biden-kamala Harris ticket. The former vice president and his history-making choice. This morning, all across the nation, little girls woke up, especially little black and brown girls, who so often feel overlooked and undervalued in their communities. But today, today just maybe they're seeing themselves for the first time in a new way. Joe, I'm so proud to stand with you. And I do so mindful of all the heroic and ambitious women before me. Whose sacrifice, determination and resilience makes my presence here today even possible. Reporter: The candidates walking out with masks on, socially distant, and almost entirely alone in a high school the reality of campaigning during a pandemic. It was Biden's first significant event in five months. Both he and Harris taking direct aim at president trump. Donald Trump has already started his attacks, calling kamala, quote, nasty. Whining, about how she's quote, mean to his appointees. It's no surprise. Because whining is what Donald Trump does best. He inherited the longest economic expansion in history. From Barack Obama and Joe Biden. And then, like everything else he inherited, he ran it straight into the ground. Reporter: The chance to witness history not lost on supporters gathered outside the gym. My colleague, Mary Bruce talking to them. I heard he was picking kamala Harris, I had to sit for a minute. Because it really was, and I told somebody earlier that it really was breathtaking. Reporter: Harris is the daughter of immigrants, a Jamaican father and Indian mother who met fighting for civil rights. Now as the first woman of color on a major political party ticket, she's become a symbol for many of what's possible. For me, she checks off all of the boxes. She comes from a very diverse, multi-cultural background. She has a 30-plus year career in fighting for what's right. Reporter: The power of this moment also hitting home for Stacy Johnson batiste, who's been friends with Harris since they were kids. She stood up for me, so when we were in kindergarten, there was a boy that had taken my art project and threw it on the ground and broke it. And she said something, got in between hem and me, and, you know, he got so upset, and we were kids, he picked up a rock, hit her in the head, and I think she still has that scar to this day. You know, that's the spirit, the fighter in her, standing up for what's right and wanting to take care of people. There would be no senator Harris as our vp without the courageous, bold candidacy of Shirley Chisholm back in '72, with ibb wells. Reporter: He is the founder of "She the people." She hosted a presidential forum that included then-candidate Harris. We didn't want to be just the backbone vote, we want to governor, we want to shape the country, we want to shape the political agenda. Now we're in a position to do that. When I saw a broken justice system, I became a lawyer to try to fix it. Reporter: She was California's top cop, serving as attorney general for 2011 to 2017. She was the first black, and Asian woman to serve. Some take issue with her decisions on policing. Has senator Harris demonstrated a willingness to re-examine those past views? She's got a real difficult job ahead. It's hard to run away from years and years and years of prosecuting black and brown bodies in the manner in which she did. She's got a mighty tall task ahead of her, in terms of convincing them that she's not the same person that she was all those years when she was California's top cop. Reporter: Over the years, she's changed her position on various issues. Senator Harris, you released your plan -- Reporter: My colleague, linsey Davis pressed her on that. You used to oppose legalization of marijuana, now you don't. You used to oppose outside investigations of police shootings, now you don't. You say you've changed because were you quote, swimming against the current and thankfully the currents have changed. But when you had the power, why didn't you try to effect change So there have been, I'm glad you asked me this question. And there have been many distortions of my record. I made a decision that if I was going to have the ability to reform the system, I would try to do did from the inside. Reporter: Do you think she needs to be better prepared to defend that record? Many believe she is political to a fault, that she will morph herself into the position that best suits the situation that she is in. And, you know, that's where candidates get into trouble. She needs to craft a message that looks forward while also acknowledging the shortcomings of the past. Because that's what they were. Reporter: During her run for president last year, the senator released a criminal justice reform plan that would in part end mandatory minimum sentences, the death penalty, solitary confinement and cash bail. This summer, she teamed up with senator Cory booker to introduce the George Floyd justice in policing act which in part would ban chokeholds and no-knock warrants, calls for independent investigations of police misconduct and establish a national police misconduct registry. What's important now is who she's showing up right now. She was one of the first senators to be out with protesters in solidarity in the wake of the murder of George Floyd, called for justice for breonna Taylor. Sponsored legislation to protect essential workers. The majority of essential workers are black and brown women. Reporter: What does she give She comes very qualified for the job. There's no question about it. For Joe Biden, who's been accused of being pulled to the left, she brings the perception of a centrist ticket, which is appealing to independents. Reporter: So far, team trump struggling to find a line of attack against Harris. Trump surrogates called Harris, a former district attorney, both too soft on criminals and too tough. I don't want someone who says that they are not going to be tough on hardened criminals. Reporter: But then. She fought to keep inmates locked up in overcrowded prisons. Reporter: In an interview with Sinclair broadcasting today, trump once again calling Harris nasty. She was the nastiest of anybody in the senate. She was the worst, meanest person to judge Kavanaugh, who became justice Kavanaugh. I've never seen anything like it. When they use the word nasty, it's shorthand for den greating the integrity and humanity of a woman. It's also racist. Reporter: Harris following in the footsteps of Geraldine faray row and Sarah Palin. They faced sexist attacks. There's something about a black woman being in that role that attracts a more sinister combination of racism and sexism. That's what she will continue to face. I think the way kamala's going to deal with attacks on her character is by sticking to the issues, sticking to the truth, and not getting derailed by mudslinging. Reporter: Harris is readying for the battle ahead, and so is her running mate. Kamala Harris has had your back, and now we have to have her back. I couldn't be prouder. To be by his side, running to represent you. The people.
This transcript has been automatically generated and may not be 100% accurate.