The former vice president's anticipated entry into the 2020 race is the last major factor looming over the opening chapter of the Democratic primary. After a likely announcement in April, Biden is hoping to seize command of the highly-fluid contest through major endorsements and possibly selecting a running mate early to highlight the argument that the party's most urgent task should be defeating President Donald Trump, Democrats familiar with his plans tell CNN.

"It can't go on like this, folks. I know I get criticized and told I get criticized by the new left," Biden said in a weekend speech to Delaware Democrats, before almost announcing he was running for president.

"I have the most progressive record of anybody running for the United States -- anybody who would run!"

His verbal slip -- intentional or not -- drew laughter in the room and considerable attention outside, but it was the words "new left" that may have offered the best clue about how he plans to run a third bid for the White House. He plans to emphasize the record of the Obama administration over his own long record from the Senate and intends to push back on any notion he's not progressive enough for today's Democratic Party.

As he prepares for a possible run, Biden has hunkered down for strategy sessions with a tight knit group of advisers and held meetings with top Democrats and elected officials. One subject of discussion has been the early selection of a running mate, which one aide said would help keep the focus of the primary fight on the ultimate goal of unseating Trump.

Last week, Biden stirred speculation as he met privately with Stacey Abrams, a Democratic rising star who ran for governor in Georgia last fall and is weighing another run for office -- potentially even the presidency. Biden requested the meeting, according to a person familiar with the sit-down, which comes as the two mull their own respective political futures.

A person familiar with the meeting said Biden and Abrams discussed a variety of topics on policy and politics, including whether she intends to run for Senate next year. The vice presidency was not formally discussed during their meeting, two people familiar with the meeting tell CNN.

Abrams also huddled with a half-dozen other Democratic presidential hopefuls, but her meeting with Biden takes on added weight because of his attempts to shore up support among black leaders amid lingering questions about his treatment of Anita Hill during the Clarence Thomas confirmation hearings and his support for a sweeping crime bill two decades ago.

Biden's team has started gaming out scenarios for what a campaign launch could look like with Wilmington, Delaware, and Scranton, Pennsylvania, where Biden was born, among several potential locations floated for an announcement rally, a source with knowledge of the discussions said. While the rest of the Democratic field settles into place, Biden's allies say the former vice president is keenly aware of the attention any announcement will draw.

"His launch will be watched by many, many eyeballs to see how he pulls it off, how much he raises," one Democratic donor in touch with Biden and his advisers said. "That's always been the question mark with him -- his discipline and his capability to execute a campaign."

One lingering question for Biden is his ability to fundraise, particularly on the small dollar, grassroots level. Other Democratic contenders like former Rep. Beto O'Rourke and Sen. Bernie Sanders have relied on massive online fundraising lists to churn out impressive fundraising figures of about $6 million.

"I think he in certain ways has been wise to string this out because the shorter the race, the better for him. He doesn't have the same demands that others have except for one that's going to be a challenge perhaps for him and that's raising money," said David Axelrod, former senior adviser to President Obama and a senior CNN political commentator. "Joe Biden's not by generation and nature a social media candidate. So he can't delay this much longer. He has to get around to the business of raising the resources that he needs."

Biden has already said he won't rely on a super PAC and as he teased a possible presidential run last week. "Our elections are drowning in money, and every dark dollar chips away at our faith in the system. You're going to hear a lot about this before it's all over, I'm not in a position to tell you now," he said.

Another question facing Biden: Can he meet the mood and the moment of today's Democratic Party? The answer is one that could dominate the next phase of the primary fight.

"I love Joe Biden. I really do," said Tom Courtney, a longtime Iowa activist and chairman of the Des Moines County Democratic Party. "But there comes a moment when it's time to not run."

That is a common refrain that voters and party officials have expressed during interviews in recent weeks, while Biden has dropped hints about jumping into the race. Many quickly qualify their adoration of the former vice president, with some saying they worry about the personal toll losing the nomination would take, while others politely argue it's time to pass the torch.

But as the conversation with Courtney lingered late last week in Burlington, Iowa, as O'Rourke visited on the first day of his candidacy, he ultimately came around to the idea of a Biden candidacy -- "if he picks a good, much younger vice president."

"Maybe that's how this will shake out in the end," said Courtney, 71, a former state senator. "We know he could beat Trump."

The announcement from Biden -- one way or the other -- will answer the last big question in the opening round of the 2020 presidential race. But if he flips the switch on a campaign, as his family and friends expect him to do, he faces the critical challenge of convincing Democrats that decades of experience are actually an asset.

For as long as he can, Biden hopes to focus on the imperative to defeat Trump, aides said, rather than dwelling on what distinguishes him from his Democratic rivals.

Biden, who has been carefully watching the field of Democratic hopefuls grow, will try to quickly seize command of the race. Democrats familiar with his plans say he intends to unveil a roster of prominent supporters, including black leaders whose endorsements are seen as critical to his candidacy, as the race moves beyond Iowa and New Hampshire.

Yet even as he campaigns on a message of experience — a candidate who doesn't need on-the-job training — Biden also has told supporters he takes nothing for granted and is keenly aware he needs to fight for the nomination. Naming an early running mate could help feed into an air of inevitability, one senior Democrat who admires Biden said, which could be problematic for his candidacy.

Biden is also cognizant of the physically and emotionally grueling nature of the upcoming campaign. Friends say Biden is bracing for "despicable attacks" on his family from President Trump along with incoming fire from his fellow Democrats.

"If you look at the 2016 campaign and the ways in which President Trump made stuff up about his opponents' family, it's likely that this will be a pretty difficult, even wuthering campaign season," Delaware Sen. Chris Coons, a close friend of Biden, said. "But look, Joe has no illusions about politics. It's not bean bag. It's a full body contact sport."

In a third bid for the presidency, Biden would carry the stature of a former vice president, but not the trappings of office, which he enjoyed during his last campaign when he ran for re-election on the Democratic ticket. There will be no Air Force Two, no motorcade and no use of the valuable list of supporters and donors from his 2008 and 2012 campaigns with Obama.

Conversations with more than a dozen party leaders and strategists in Iowa, all of whom take pains to point out their deep respect for Biden, wonder how he will compete in what is expected to be a record-setting turnout in the Iowa caucuses. His ability to attract new and younger voters could be among his biggest challenges.

"I would like to see him run. But whether he gets the nomination or not, I don't know," said Jeff Heland, a former mayor of Burlington, Iowa, said of Biden. "I would be thrilled by someone who inspires us -- whoever that is."