“If there’s one thing we’ve learned as a country from moments of great crisis, it’s that the spirit of looking out for one another can’t be restricted to our homes or our workplaces, or our neighborhoods or our houses of worship. It also has to be reflected in our national government,” Obama said in a nearly 12-minutevideo message released Tuesday.

“The kind of leadership that’s guided by knowledge and experience, honesty and humility, empathy and grace,” he continued. “That kind of leadership doesn’t just belong in our state capitals and mayor’s offices. It belongs in the White House. And that’s why I’m so proud to endorse Joe Biden for President of the United States.”

The quick succession of endorsements so soon after Sanders dropped out of the race provided a rebuke to Trump’s attempts to sow discord within the party; the president has repeatedly sought to raise doubts about Obama and Sanders’ true allegiance to Biden.

The endorsements also underscored Biden’s role as a coalition builder, which Democrats intend to hold up as a major contrast to Trump.

Obama and Sanders struck similar notes in their remarks, contrasting Trump’s leadership style — which they characterized as self-serving, dictatorial and dangerous — to Biden’s, calling him compassionate and experienced.

Biden’s aides pointed to the significance of the timing of the events, noting this is the earliest that a Democratic nomination has been conclusively wrapped up since 2004.

In its outreach to former rivals, Biden’s campaign has repeatedly argued that it was the bitter intra-party divisions of 2016 that contributed to Hillary Clinton’s defeat in the fall. Disaffected voters, including many loyal Sanders supporters, stayed home in 2016.

All along, Biden has steadily collected the support of his major competitors by noting that he intends to serve as a bridge to the next generation of Democratic leadership. In recent weeks, the former vice president has taken on a more expansive role as the presumptive nominee and head of the party.

He has been careful to praise Sanders effusively, adopted major policy proposals from Warren and pledged to set up policy committees with Sanders to help adopt platforms that emerged from the Vermont senator’s progressive movement.

Biden’s efforts to unite the party included chiseling away at the iciness between Warren and himself. The two have personally spoken numerous times since Super Tuesday — and several times in recent weeks — sources familiar with the conversations say. The Massachusetts senator’s endorsement is “coming soon,” those sources said, and is merely awaiting a green light from Biden’s camp.

Obama’s highly anticipated foray into the 2020 race after declining to back a candidate during the primary contest delivered a welcome bite of the news cycle — no small accomplishment during the coronavirus pandemic.

While widely expected, it represents a new phase in the general election campaign against Trump, unlocking the Democratic Party’s most powerful surrogate for Biden at a time when his campaign has struggled to cultivate momentum against the backdrop of the outbreak in the U.S.

Although Bidenmaintained during the primary that he had asked Obama not to endorse any particular Democratic candidate — insisting that “whoever wins this nomination should win it on their own merits” — he relentlesslyinvoked his eight years of service under the former president and warm, personal relationship with him to court voters.

Biden’s efforts to align himself so closely with Obama, even as the previous administration’s policies came under occasional scrutiny from the party’s left flank, were ultimately successful in propelling him past more progressive rivals to become Democrats’ pick to challenge Trump in November.

His tenure as Obama’s No. 2 also contributed immeasurably to Biden’s firewall of support among African-American voters and proved foundational to the campaign’s argument that the former vice president was a capable leader ready to assume the responsibilities of the Oval Office.

Weighing in on the endorsement Tuesday, Brad Parscale, Trump’s reelection campaign manager, asserted that Obama “spent much of the last five years urging Joe Biden not to run for president out of fear that he would embarrass himself,” and now “has no other choice but to support him.”

“Obama was right in the first place: Biden is a bad candidate who will embarrass himself and his party,” Parscale said in a statement. “President Trump will destroy him.”

As a historically crowded and diverse field of White House hopefuls competed for the Democratic nomination over the past year, Obama’s public statements and remarks on the state of the race were closely parsed for potential clues regarding his preference of candidate and aspirations for the future of the party.

When Biden officially entered the race last April, the former president’s spokeswomansaid Obama “relied on the vice president’s knowledge, insight and judgment throughout both campaigns and the entire presidency,” and added that the two men “forged a special bond over the last 10 years.”

In November, Obama memorablywarned a group of liberal donors that the “average American doesn’t think we have to completely tear down the system and remake it,” arguing that voters “just don’t want to see crazy stuff” and “are not driven by the same views that are reflected on certain, you know, left-leaning Twitter feeds.”

He also reportedlyurged Democrats later that same month to “chill out” about the party’s pool of candidates and expressed suspicion toward “purity tests during elections.”