DES MOINES, Iowa (AP) — The campaign trips to Iowa are becoming more frequent, the pleas to voters more urgent and the potential for coming up short more vivid.
The three-month sprint to the Iowa caucuses begins Friday when more than a dozen Democratic presidential candidates make their increasingly urgent pitches at the state party's marquee annual fundraiser.
Fourteen White House hopefuls are scheduled to speak to the more than 13,000 Democratic activists, party volunteers and campaign supporters who are expected to convene in Des Moines for the Iowa Democratic Party's Liberty and Justice Celebration.
The event, which amounts to the largest gathering of Democrats in an early voting state, is so big that it will serve as something of a dress rehearsal for the Feb. 3 caucuses. The momentum of candidates on the rise will be tested while lagging contenders will face further questions about why they're staying in the race.
The event ushers in a new, critical chapter of the campaign. Candidates must now move beyond simply introducing themselves to voters and activists and focus on perfect a grassroots strategy to ensure their supporters show up at the caucus.
"This dinner is an epic moment," said former state Democratic Chairwoman Sue Dvorsky, who has endorsed California Sen. Kamala Harris. "It kicks off an entirely different phase of the national campaign."
The damp, chilly streets of downtown Des Moines buzzed with the intensifying campaign.
Supporters and campaign volunteers for the candidates waved signs at busy street corners, and congregated in chanting droves outside Wells Fargo Arena, where the evening event takes place.
The leading candidates are going into the banquet with a different set of advantages and vulnerabilities.
Former Vice President Joe Biden faces questions about the intensity of his support in Iowa. His campaign plans to pack the audience with thousands of supporters and flood the hall with members of the International Association of Fire Fighters, a union that threw its support to Biden early in the race.
But his early lead in Iowa is being challenged by Sen. Elizabeth Warren. Pete Buttigieg, the mayor of South Bend, Indiana, is building a following in the state that would have seemed far-fetched six months ago. And Sen. Bernie Sanders has a steady base of support that means he can't be written off.
Buttigieg has the largest presence planned for the event, having bought thousands of seats for supporters in the arena, hosting an overflow room in the hall, leading a pre-event rally expected to draw hundreds just blocks away and embarking on a three-day bus tour through the state afterward.
Though public polls have shown the 37-year-old mayor trailing Warren, Biden and Sanders, Buttigieg has seized on curiosity about his candidacy to mount an aggressive organizing campaign seen as having traction in recent months. Beyond his youth, Buttigieg is the first major gay candidate for president and is an Afghanistan war veteran and Rhodes scholar.
"It kind of feels Buttigieg has some wind in his sails," said Jeff Link, a veteran Iowa Democratic campaign operative.
Warren enters the weekend under pressure to prove that she can sustain the momentum that built around her campaign over the summer. She brought the audience in a crowded auditorium to its feet in August when she spoke at another Democratic dinner. But as her candidacy rises, she's come under growing scrutiny, especially when it comes to questions of how she would implement and pay for her ambitious policy proposals.
Former Iowa Gov. Tom Vilsack said the race had entered a phase more serious than the festival-like atmosphere in Des Moines suggested.
Vilsack suggested Friday that Warren's plan to finance her universal health care proposal with higher-still taxes on wealth Americans is unrealistic.
"I really, honestly believe people need to get serious about this and say, 'O.K., great, this is a great plan, how are you going to get it passed?'" Vilsack said Friday. Vilsack, who was U.S. secretary of agriculture during the Obama administration, has consulted several candidates including Warren on rural issues.
She released new details on Friday about how she would implement a "Medicare for All" program, but independent experts quickly questioned some of her estimates.
Sanders, meanwhile, is just weeks removed from a heart attack that took him off the campaign trail for several days. He will likely need to demonstrate that he's up to the pressure of campaigning.
A New York Times/Sienna College poll of likely caucusgoers released on Friday found Warren, Sanders, Buttigieg and Biden bunched together at the top of the field in Iowa.
One person missing from the weekend's activities: Hawaii Rep. Tulsi Gabbard, whom some Democrats worry could mount a third-party bid for the presidency.
All of the candidates can look to history for reassurance that a strong performance at the dinner can change the trajectory of their campaigns.
In 1999, then-Vice President Al Gore effectively blocked former New Jersey Sen. Bill Bradley's advance with the chant during his speech "stay and fight," a nudge at Bradley for leaving the Senate.
Four years later, Massachusetts Sen. John Kerry held off a dire challenge from Howard Dean at the event.
"We need answers not just anger," Kerry said, in a hit at the anti-war Vermont governor who had stirred passions on the left but worried others for challenging a wartime President George W. Bush. "Iowa, don't just send them a message. Send them a president."
More notably, then-Illinois Sen. Barack Obama in 2007 threw down the gauntlet against national Democratic front-runner Hillary Clinton, declaring "triangulating and poll-driven positions, because we're worried about what Mitt or Rudy might say about us, just won't do."