Sen. Kamala Harris (D-CA) talks to reporters with Sen. Patrick Leahy (D-VT) (R) following the weekly Democratic Senate policy luncheon in the U.S. Capitol November 27, 2018 in Washington, DC.

Senator Kamala Harris outlined her vision for a unified America while promoting her new book in New York City, with the California Democrat criticizing President Donald Trump over his insistence on erecting a wall along the Southern U.S. border.

The book and cross-country promotional tour comes as the 54-year-old crafts an image as a contender for higher office. Harris is widely expected to announce a 2020 presidential bid in what is shaping up to be a crowded field of fellow Democrats.

Moments after Harris walked on stage at the 92nd Street Y in Manhattan, an audience member shouted "Forty six!," a reference to the next U.S. president. The raucous applause from the sold-out crowd was a sign of enthusiasm for her potential candidacy.

"The vast majority of us have so much more in common than what separates us," Harris said, repeating a line that also appears in her book, "The Truths We Hold: An American Journey." Released on Tuesday, the book intertwines stories from Harris's upbringing and personal life with policy proposals that could form the foundation of a campaign.

On Friday, Harris sounded off on a wide array of potential campaign themes. She called the war on drugs "ineffective" and railed against the country's cash bail system that disproportionately affects the poor as "not reflective of a system of justice." She also touted the 2017 bill she introduced with Sen. Rand Paul, R-Ky., to dis-incentivize states from using cash bail, as evidence of her bipartisan deal-making skills.

The thrust of Harris' book and remarks in New York addressed finding commonality among diversity, a potential 2020 campaign rallying cry in a political climate that's deeply fractured. However, she wasted little time in hitting out at Trump for the impasse over border security that's forced a government shutdown that's lasted three weeks.

Harris derided President Trump's proposed border wall as a "vanity project" as the government's temporary closure broke the record for the longest ever, and even linked it to Special Counsel Robert Mueller's probe of Russian interference in the 2016 election.

The fight over the wall is a "distraction from the fact that you've got Mueller investigating" people close to Trump, Harris told the audience.