Harris' announcement has been met with a mixture of support and skepticism. Many liberals have criticized her record as a former California prosecutor.
In a press conference on Monday at Howard University, Harris addressed concerns about her days as a prosecutor, saying there were some cases in which she regrets not being able to do more.
"I can tell you of the cases where I really regret that we were not able to charge somebody that molested a child but the evidence wasn't there," HuffingtonPost reports her saying at her alma mater. "There are cases ... where there were folks who made a decision in my office who did not consult with me and I wish they had. But again, I take full responsibility for those decisions."
Harris continued by citing the things she did as a prosecutor that she is proud of, like implementing a program where first-time nonviolent offenders can have their charges dismissed if they complete vocational training.
"There are fundamental flaws in the criminal justice system and ... this criminal justice system needs to be reformed," she added.
In addition to criminal justice reform, aides close to Harris tell The Washington Post that the presidential candidate also plans to propose bail reform, a $3 trillion tax plan, a tax credit for low-income renters and a Medicare-for-all healthcare plan.
Harris, who is currently the only black woman in the Senate, has gained popularity for her tough questioning of Trump nominees, including Supreme Court nominee Brett Kavanaugh and former Attorney General Jeff Sessions. She's also known as being a tough critic of President Trump's immigration policies and has pushed for policies to protect immigrants from deportation.
After making her announcement on "Good Morning America," the senator released a video debuting her campaign slogan as "Kamala Harris: For the People."
"The future of our country depends on you, and millions of others, lifting our voices to fight for our American values," she said in the video. "Let's do this together. Let's claim our future for ourselves, for our children and for our country."
Harris, who has reportedly raised $1.5 million since her announcement, is the fourth woman to enter the 2020 Democratic presidential race. So far, Sen. Elizabeth Warren, Sen. Kirsten Gillibrand and Congresswoman Tulsi Gabbard have all announced presidential campaigns.
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These are the women making history as the 116th Congress is sworn in