"I am not running against the Democrats", although the party has shifted "far, far left", Schultz said, insisting "nobody" wants to see Trump out of office more than he does. Senators Elizabeth Warren, of MA, and Kirsten Gillibrand, of NY, have announced exploratory committees.
"She believed a critical way to keep kids out of jail when they're older is to keep them in school when they're young", a campaign spokesperson told HuffPost on Tuesday.
"It's not that it's not American", Schultz said.
Ms Harris, known for her rigorous questioning of Mr Trump's nominees, has vowed to "bring our voices together". We know it ended a little short for him.
Ms Harris added: "So today I say to you: these are not ordinary times, and this will not be an ordinary election, but this is our America".
"There were moments in 2008 when Obama would get a lead or our opponents would go through tough spots and we would default to a more conventional, (risk averse) campaign and we always suffered when that happened".
Harris also did not shy away from taking on Trump directly, saying the USA welcomes refugees and calling the wall that Trump wants to build at the southern border a "medieval vanity project" that would not actually stop transnational gangs, which she noted she battled as state attorney general.
Harris, a former prosecutor and California state attorney general, argued that solutions, such as an assault-weapons ban and universal-background-check legislation, have been devised and proven effective, but can not be implemented because her colleagues in Congress lack "the courage to act the right way".
That said, she also maintained record-high conviction rates as district attorney, and maintained most status quo positions on issues of over-incarceration and the death penalty.
But her record has also caused controversy among progressives.
The announcement was met with immediate criticism by her political opponents.
During her speech, Ms. Harris appeared to take on power in various forms - she referred to "the arrogance of power" of big banks and said that big pharmaceutical companies had unleashed the opioid crisis.
Second, government run health insurance is not the same thing as medical care. There's room for an anti-Trump centrist in this electorate - and that running space has been created by a Democratic Party beholden to its radical base.
Her tweet came after Brown wrote a column for the San Francisco Chronicle in which he admits to engaging in the relationship with Harris.
Civil rights advocate Lateefah Simon responded: "(Ms Harris) became a prosecutor to give the job a perspective it had sorely lacked: "a voice for the voiceless and vulnerable. With equal emotion, Harris denounced the Charlottesville riots, the Pittsburgh synagogue attack, and Trump's border separation policy as "not Our America".
One distinct advantage for Harris is the shift that her home state has made in the primary calendar.