A who's who of prospects for the Democratic 2020 presidential nomination -- none declared, of course, but none ruling national ambitions out, either -- will appear at a daylong event hosted by the Center for American Progress.
The liberal think tank's "Ideas Conference" is poised to allow those vying to lead the party to test-drive their economic messages and arguments a year and a half before any of them would actually have to head to Iowa and New Hampshire to campaign.
Massachusetts Sen. Elizabeth Warren is set to deliver the lunchtime keynote, while New Jersey Sen. Cory Booker will deliver the closing speech. Also on tap -- and seen as potential 2020 candidates -- are New York Sen. Kirsten Gillibrand, California Sen. Kamala Harris, Minnesota Sen. Amy Klobuchar, Connecticut Sen. Chris Murphy and Oregon Sen. Jeff Merkley.
From the executive ranks, Los Angeles Mayor Eric Garcetti will open the event, while Montana Gov. Steve Bullock, Virginia Gov. Terry McAuliffe and North Carolina Gov. Roy Cooper are also set for speaking roles.
Other leading Democrats, including House Minority Leader Nancy Pelosi, liberal mega-donor Tom Steyer, Gold Star father Khizr Khan and influential activists are slated to appear.
The event comes as the Democratic Party -- energized by a protest movement unlike anything the party has seen for decades -- searches for new voices at its forefront.
Former President Barack Obama has departed the political stage for now, and former Vice President Joe Biden told a crowd recently that he will not run in 2020.
It's left Democrats facing a nominating contest much more like 2004, when John Kerry emerged from a wide-open field, or 2008, when Obama bested Hillary Clinton and John Edwards, than recent contests with well-established incumbents or front-runners.
By this stage in those cycles, prospective candidates "were working pretty hard at it" behind the scenes, said Bob Shrum, a veteran of Democratic campaigns, including Al Gore's in 2000 and Kerry's in 2004.
"There's a lot more happening behind the scenes in terms of folks maneuvering to line up fundraisers, political talent, how they're going to put a campaign together," Shrum said.
So at a cattle call like Tuesday's, he said, "you want to do well."
"First of all, you have to stand up to Trump -- visibly, consistently and cogently -- on everything from health care to tax fairness to the Russia investigation," he said. "Two, articulate a compelling message on economic and social justice, and you can't choose one over the other."
Vermont Sen. Bernie Sanders has by far the largest megaphone of any Democrat -- and his massive email list built in 2016 would give him a huge fundraising advantage. But Sanders would also be 79 years old on Election Day 2020.
For other potential candidates, the 2018 midterm cycle is more important. It's an opportunity to curry favor with House members and senators on the ballot this cycle by campaigning and raising money for them while also elevating their own profiles and meeting local party honchos, said Mitch Stewart, a founding partner of 270 Strategies and a veteran of Obama's campaigns.
Stewart argued cattle calls are "less important now" than they were in 2004 and 2008 -- in part because social media tools like Twitter allow more opportunities for potential candidates to reach wide swaths of the party's electorate. He pointed to Booker's Twitter account during his tenure as Newark mayor as an example.
But events like Tuesday's also offer potential candidates opportunities to test-drive a message that reaches beyond an energetic base, Stewart said.
"What I haven't really seen any of the potential Democratic candidates do is put out a positive message that can try to break the bond that Trump has with some of his voters," he said.
"And I think right now, it's just good to have activism, it's good to have energy," he said. "But at some point, a candidate's going to have to channel that energy into something a bit more constructive and talk about how Democrats offer a different economic vision that can peel off some of these voters that were sort of duped by Trump."