On immigration, she blasted Trump's "inhumane" policy that has led to child separations at the border, and said Trump has failed young immigrants who were brought to the country as children. "He was aspirational like our country is aspirational", she said of the civil rights leader.
One reason for the racial scrutiny Harris was receiving was because of her past record as the district attorney in San Francisco.
Harris's launch has drawn heavily on symbolism.
Senator Kamala Harris holds a rally to launch her 2020 presidential campaign in her hometown of Oakland, California, U.S., January 27, 2019. "My mother used to say, "Don't sit around and complain about things, do something", Ms. Harris said.
Exactly one week ago on Dr. Martin Luther King, Jr. Harris also has the backing of Oakland Mayor Libby Schaaf.
Harris' first news conference as a candidate was on the campus of Howard University, the historically black college in the nation's capital that she attended as an undergraduate. The state of California has played a leading role in resistance to the presidency of Donald Trump.
Michael Ahrens, a spokesman for the Republican National Committee, called it "fitting" that Harris chose "the most liberal district in deep-blue California to launch her campaign".
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Some commentators have been drawing parallels between Harris and Obama since early on in the California senator's political career, while others said such comparisons were reductive, with one writer, Holly Thomas, calling the urge to compare the two "symptomatic of a lazy habit that infantilizes high-profile women in America and overseas and skims over the personal details and unique circumstances that shaped them". But at other moments, she hints at a harder edge than the "no-drama" former president.
"When you were [California's] attorney general, you opposed legislation that would have required your office to investigate fatal shootings involving police officers".
Harris is among the first major Democrats to jump into what is expected to be a crowded 2020 presidential contest.
In addition to Harris, Senators Elizabeth Warren, Kirsten Gillibrand and former U.S. Secretary of Housing and Urban Development Julián Castro have already announced plans to join the presidential race, while former Vice President Joe Biden, former Texas Representative Beto O'Rourke, Senators Cory Booker and Bernie Sanders and others are still mulling over whether to throw their hat into the ring.
Harris joins early Democratic contenders including former Housing and Urban Development Secretary Julian Castro, Maryland's John Delaney, Hawaii's Tulsi Gabbard and NY senator Kirsten Gillibrand.
Her town hall will be live from Iowa.
Harris laid out what looks like a catchphrase marking her campaign: "Speak truth".
But Harris' early and energetic entry into the race has given her a leg up.