Donald Trump launched his campaign for president 2½ years ago with a famous ride down the golden escalator of his office tower, projecting an image of wealth and plutocratic power.

Cory Booker took a dramatically different route Friday as he plunged into the 2020 presidential race.

Booker strode along the sidewalk toward his home in the central ward in Newark, a struggling city he once led as its charismatic mayor.

Trump played to his base of white male voters. Booker took aim at African-American voters, a loyal constituency that he'll need to consolidate if he is to have any chance of capturing the Democratic nomination.

"My parents knew that if we worked together, blacks and whites, Christians and Jews, that we could upend Jim Crow,'' Booker said during a news conference outside his home Friday, invoking some of the spirit and rhetoric of the civil rights movement in the 1960s.

African-American voters have long been a crucial voting bloc in Democratic presidential primaries. It helped Barack Obama pull away from Hillary Clinton in 2008. Eight years later, the same voters helped Hillary Clinton put distance between her and her one rival, Sen. Bernie Sanders of Vermont.

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Some analysts estimate that African-Americans represent 27 percent of Democratic primary voters — a key prize this year, given a field crowded by possibly as many as 20 candidates.

Seizing control of the black vote — and early in the primary contest season — could be key to launching Booker into the top tier of candidates with enough momentum to survive the long slog of the "Super Tuesday" primaries and beyond. But Booker will likely face a fierce challenge from U.S. Sen. Kamala Harris of California, an African-American and rising star in Democratic Party circles who entered the race on Martin Luther King Jr. Day last month.

"No person has won the Democratic nomination in the modern era without the overwhelming support of African-American voters,'' according to a strategy memo by Steve Phillips, a San Francisco lawyer and civil rights activist whose independent super PAC is expected to spend $10 million to boost Booker's candidacy.

"While the 2020 field may end up with multiple black Democratic candidates, there will even be more white candidates splitting the pie,'' wrote Phillips, a Stanford classmate of Booker's. "As such, each candidate's strength among black voters, his or her ability to inspire and mobilize African-Americans and make them feel seen and heard on issues that matter to them, will still be key to electoral success."

Booker appeared to have gotten the memo.

During his news conference, Booker touted policy issues that have been priorities among minority populations. He discussed his criminal justice reform legislation, designed to end "mass incarceration" He spoke at length about lead poisoning and the need to replace aging water supply systems in the nation's poorest cities — an issue heightened by the tainted water supplies in Flint, Mich.

Booker, who settled in a crime-infested housing project when he first moved to the city in the 1990s, expressed his support of public school teachers while carefully avoiding a full-throated defense of charter schools, which is opposed by teachers' unions, a powerful Democratic Party constituency.

And Booker, who attended Stanford, Oxford and Yale Law School, invoked the imagery and themes of the civil rights era throughout his news conference. He cited as his inspiration unarmed "heroes" who took on "dogs and billy clubs and brought down Jim Crow."

Booker also described "love" as a force of political change, a theme that echoed King, who once argued that "power at its best is love, implementing the demands of justice."

"Patriotism is love of country, and you can’t love your country unless you love your fellow countrymen and women,'' Booker said. He also discussed how his parents confronted redlining when they first sought to buy a home in the suburbs. The family settled in Harrington Park in Bergen County.

At one point, Booker was interrupted by a Spanish-speaking woman cheering him on from a second-floor balcony across the street. A chain-link fence served as a backdrop as he took questions. And Booker referred to the local tenant-rights activists who urged him to run for City Council in the 1990s.

"I got my B.A. from Stanford but I got my Ph.D. on the streets of Newark,'' he said.

Booker rarely mentioned Trump, who is deeply unpopular among African-American voters, preferring to stick to more aspirational themes. Yet, when asked by a reporter if he thought Trump was a racist, Booker replied, "I don't know the heart of anybody, but there are people who profess the ideology of white supremacy who use his words."

Patrick Murray, the Monmouth University pollster who watched the news conference from the sidewalk, said the polling he has seen so far shows Booker with an "extremely high favorability rating" among African-American voters.

That could become a crucial advantage in South Carolina, where African-Americans made up 61 percent of voters in the Democratic primary in 2016, according to exit polls. It's also a crucial early primary, which has historically served the role of winnowing the field.

"That is one reason why he had this announcement on his doorstep in the city of Newark, to show that this is who he is, this is where he comes from," Murray said.

Booker will inevitably face the challenge of broadening his appeal beyond his base if he does well in the South Carolina primary, Murray said. "But the first step is you got to become one of those three or four" finalists, he said.

Booker took the first step in that direction Friday as he strode down the sidewalk in his Newark neighborhood.