In the wake of President Joe Biden's unexpected withdrawal from the 2024 presidential race, Vice President Kamala Harris is rapidly mobilizing to secure the Democratic nomination. Biden, 81, announced his decision to step aside on Sunday, citing growing opposition within his party and concerns over his ability to lead. Harris, 59, immediately began her campaign to lock up the nomination, with an official statement emphasizing her commitment to unite the party and defeat former President Donald Trump in the upcoming election.

"My intention is to earn and win this nomination," Harris stated. "I will do everything in my power to unite the Democratic Party - and unite our nation - to defeat Donald Trump."

Harris's announcement was followed by a flurry of activity as campaign officials and allies made hundreds of calls to delegates ahead of the Democratic National Convention scheduled for August 19-22 in Chicago. Prominent Democrats, including potential challengers like California Governor Gavin Newsom, quickly endorsed her, indicating a strong initial show of support. However, the path to securing the nomination is not without its challenges.

Biden's withdrawal was precipitated by a disastrous debate performance against Trump on June 27, which led many Democrats to question his viability as a candidate. Senior Republicans have since called for Biden's resignation, arguing that if he is unfit to campaign, he is unfit to govern. Despite these calls, Biden has pledged to serve out the remainder of his term, which ends on January 20, 2025.

In his statement endorsing Harris, Biden highlighted their shared achievements and urged Democrats to rally behind her. "My very first decision as the party nominee in 2020 was to pick Kamala Harris as my Vice President. And it's been the best decision I've made. Today I want to offer my full support and endorsement for Kamala to be the nominee of our party this year. Democrats - it's time to come together and beat Trump. Let's do this."

The support from high-profile figures like former President Bill Clinton and former Secretary of State Hillary Clinton, who endorsed Harris shortly after Biden's announcement, has bolstered her campaign. "We join millions of Americans in thanking President Biden for all he has accomplished," the Clintons said in a joint statement. "We are honored to join the President in endorsing Vice President Harris and will do whatever we can to support her."

Despite the early endorsements, some Democrats remain cautious. Former President Barack Obama praised Biden's decision but did not immediately endorse Harris, instead expressing confidence that the party would choose an outstanding nominee. This sentiment reflects a broader uncertainty within the party about Harris's ability to galvanize support and win against Trump.

Polling data suggests that Harris performs similarly to Biden against Trump. A Reuters/Ipsos poll conducted shortly after an assassination attempt on Trump on July 13 showed Harris and Trump tied with 44% support each, while Trump led Biden by a narrow margin of 43% to 41%. This statistical dead heat underscores the challenges Harris faces in convincing the electorate of her candidacy's viability.

Harris's campaign is expected to emphasize her strong stance on abortion rights, an issue that resonates with younger voters and more liberal Democrats. As Vice President, she has been a vocal advocate for reproductive health rights, a contrast to Biden's more reserved approach. "Most significantly, Harris would be the face of the drive to protect abortion rights," said Larry Levitt, executive vice president for health policy at KFF.

However, Harris must also address other critical issues such as the economy, immigration, and healthcare to build a broad coalition of support. "She's got to concentrate, if she wants to win, on issues that have a broad appeal," said Joseph Antos of the American Enterprise Institute. "Cost is one and access to treatments is another big issue."

Reuters and NPR contrubited to this report.