Sen. Kamala Harris, D-Calif., excoriated President Trump without mentioning him by name during the official launch of her 2020 presidential campaign on Sunday.

Harris, 54, speaking at a rally attended by 20,000 outside Oakland City Hall in her Northern California hometown, told the crowd that her "For the People" tag line was more than a campaign slogan. Instead, the one-term senator said it was the "guide" to her life's work as a lawyer, San Francisco's district attorney, the state's attorney general, and potentially as the country's next commander in chief.

"We are here because the American Dream and our American democracy are under attack and on the line like never before. And we are here at this moment in time because we must answer a fundamental question: Who are we, who are we as Americans?" she said. "So, let’s answer that question to the world. To each other. Right here. Right now. America, we are better than this."

Harris, pushing a populist message, tore into Trump for his confrontational approach to the press and his hesitancy to disavow white nationalists and white supremacists. But the daughter of immigrants saved her most passionate rebuke for Trump's hard-line immigration polices.

"When we have children in cages, crying for their mothers and fathers, don't you dare call that border security. That's a human rights abuse. And that's not our America," she said.

Promising to run on a five-fold platform focused on government-financed healthcare, a middle-class pay increase and tax cut, improved access to education, criminal justice reform, and climate change, Harris officially entered the race on Sunday on the back of momentum she has built since embarking on a national book tour this month to promote her memoir, The Truths We Hold. While the likely crowded primary field is still taking shape, her campaign kickoff was carried by all three major cable news networks, and this week she earned the approval of MSNBC heavyweight Rachel Maddow.

Harris initially announced on Monday, Martin Luther King Jr. Day, that she would be launching a Democratic bid for president.

The Republican National Committee quickly pounced on Harris' speech Sunday, describing her as an extreme liberal from deep blue California who would fail to gain traction in a national vote.

"It’s fitting that Harris chose the most liberal district in deep-blue California to launch her campaign," RNC spokesman Michael Ahrens said in a statement. "Government-run health care, weaker borders and higher taxes might be popular there, but her liberal policies are totally out-of-step with most Americans. President Trump has led this country to record economic highs and strengthened our national security, and it’s why he’s going to be re-elected in 2020.”

Harris is now one of more than half a dozen members of her party who have officially made moves toward the White House. She is joined by Sens. Kirsten Gillibrand of New York and Elizabeth Warren of Massachusetts, Rep. Tulsi Gabbard of Hawaii, former Rep. John Delaney of Maryland, Obama-era housing secretary Julian Castro, South Bend, Ind., Mayor Pete Buttigieg, and entrepreneur Andrew Yang.

Harris' next stop on the campaign trail will be a trip to early-voting Iowa on Monday ahead of a town hall event televised by CNN that evening.