The endorsements of Joe Biden came fast and furious on Wednesday morning – as the coalescing around the Democrats’ presumptive presidential nominee went into overdrive.

The first came from Sen. Elizabeth Warren of Massachusetts – the progressive firebrand who battled the former vice president during the primaries.

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She was quickly followed by Tammy Baldwin, the liberal senator from the crucial battleground state of Wisconsin. Minutes later came endorsements from Sens. Debbie Stabenow and Gary Peters of Michigan, another key battleground in November’s general election. Add to that Rep. Adam Schiff, the well-known House Intelligence Committee chairman, and Valerie Jarrett, who was a longtime leading adviser to President Obama.

The endorsements came one day after the former president – Biden’s boss for eight years – came off the sidelines and officially backed his one-time running mate. Obama’s endorsement followed by a day the backing of Biden by Sen. Bernie Sanders of Vermont, who was the last remaining rival for the party’s nomination until he suspended his campaign last week.

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With President Trump angling for a second term in the White House, even progressive rock star Rep. Alexandria Ocasio-Cortez, D-N.Y. – a major Sanders supporter who’s been very vocal about her differences with the former vice president – said Wednesday on “The View” that “I think it’s really important that we rally behind our Democratic nominee in November.”

After marathon nomination battles in 2008 between Obama and then-Sen. Hillary Clinton, and in 2016 between Clinton and Sanders, Biden’s earned presumptive presidential nominee status quicker than any Democrat since then-Sen. John Kerry of Massachusetts wrapped up the 2004 nomination in early March of that year (there was no primary contest in 2012 as Obama ran for re-election).

“Vice President Biden wrapped up one of the smoothest nomination processes in memory,” noted strategic communications consultant Ben LaBolt, who served as national press secretary for Obama’s 2012 reelection campaign. “He had an incredible come-from-behind victory in which the party – from moderates to hardcore progressives -- embraced his candidacy by the spring.”

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LaBolt emphasized that Democrats from the left to the center “all understand the perilous threat of a second Trump term – and Biden is not only a known and trusted commodity, but he has clearly communicated to supporters of Sens. Sanders and Warren that he hears them and will push for bold change.”

And, pointing to the coronavirus pandemic, LaBolt said the rush to rally around Biden “was accentuated by the crisis environment we are operating in. It’s not time for intraparty squabbles – it’s time for a unified vision of how we both address the crisis and rebuild and restore the country as it is mitigated.”

Democrats desperately have been trying to avoid a repeat of the 2016 election, when Sanders endorsed nominee Hillary Clinton in July of that year after a long and bitter primary battle. But, plenty of his legions of younger and progressive supporters either stood on the sidelines or voted for a different candidate in November, helping Trump upset Clinton and win the White House.

Longtime Republican strategist Colin Reed – a veteran of the 2012 Romney presidential campaign – said Democrats have been trying to learn the lessons from four years ago. He stressed, “Trying to avoid the mistakes of the past is always a smart move in politics.”

But, not all Democrats have been singing Kumbaya.

Former Sanders campaign National Press Secretary Briahna Joy Gray took to social media to announce that she refused to back Biden. And, plenty of Sanders supporters have been grumbling.

While endorsing Biden, the senator himself shined a spotlight on some key policy differences between himself and the presumptive nominee.

“It’s no great secret out there, Joe, that you and I have our differences, and we’re not going to paper them over,” he emphasized Monday.

And, Ocasio-Cortez called for Biden – in order to win the trust of progressive voters – to shift to the left on the key issues of immigration, health care and climate change. “I don’t think that the vice president has a climate-change policy that is sufficient right now,” the congresswoman told Politico on Wednesday. “I’d like to see us really work on that.”

Julia Barnes – a consultant for the Democrats and top staffer on the 2016 Sanders presidential campaign who stayed neutral in the 2020 primaries – highlighted, “Despite the endorsements, I think there’s still a lot of outreach work that needs to happen.”

She continued, “We see every year that the power of endorsements becomes more contingent on the place where volunteers and activists are choosing to spend their energy. So, I hope very much that the Biden campaign would do very concentrated outreach to include a lot of those people in their discussions moving forward.”

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Reed noted, “These party leaders getting in line is helpful, but we’ll have to watch... whether or not the progressive and populist coalition Bernie Sanders assembled will get on board.”

And, he warned, “A lot of these people who got involved in politics because of Bernie Sanders have very large social media followings and influential relationships with reporters and they can make life difficult for former Vice President Biden if they don’t follow their leaders and get on board.”