Des Moines (CNN) Ninety-four days from the Iowa caucuses , the Democratic presidential contenders each got 12 minutes to try to impress likely voters on the state party's biggest night of the year .

The Iowa Democratic Party's Liberty and Justice Celebration -- the renamed former Jefferson-Jackson Dinner -- once helped launch then-Sen. Barack Obama ahead of Hillary Clinton in the lead-up to the 2008 Iowa Democratic caucuses.

Now, 12 years later, candidates sought their own breakout moments. On Friday, Massachusetts Sen. Elizabeth Warren and South Bend, Indiana, Mayor Pete Buttigieg showed why they've been steadily rising in the polls, bringing the most supporters and delivering the clearest arguments of the night.

Buttigieg offered an optimistic vision for a post-Trump America. He said he had "seen in the dust of a war zone Americans who have nothing in common besides the flags on our shoulders learn to trust each other with our lives" and "seen in the ruins of factories, my city answer those who said we were a dying community by rising up together to build a better future."

Warren, meanwhile, was the most aggressive in taking on other Democrats -- delivering perhaps the night's most memorable line.

"I'm not running some consultant-driven campaign with some vague ideas that are designed not to offend anyone," she said.

Friday also brought a dose of reality for candidates polling in the low single digits. Few of the attendees actually stuck around to hear from them, underscoring the reality that with such a crowded Democratic field, voters are eager to pare down their options.

Here are seven takeaways from the Liberty and Justice Celebration:

Flexing organizational muscle

With more than 13,000 tickets sold, Friday night was the biggest Democratic event of the year in Iowa.

That meant candidates didn't just need to deliver stirring speeches -- they needed to arrive with a show of force, too, to show caucus-goers that they have energy and momentum behind their campaigns.

Warren rolled into Des Moines escorted by a giant inflatable golden retriever. It was a nod to her dog Bailey, and it came with two pennies on its collar -- a reference to Warren's proposed 2% wealth tax.

Inside the arena, there was no doubt that -- much like the Polk County Steak Fry six weeks earlier -- Warren and Buttigieg had bought the most tickets and had the rowdiest supporters.

During their speeches, Buttigieg's supporters waved light-up thundersticks. Warren's backers unfurled a giant "Win with Warren" sign.

California Sen. Kamala Harris, who danced her way into the arena, also had a huge cheering section.

New Jersey Sen. Cory Booker's faithful brought giant light-up letters that spelled words like "Rise" that echo Booker's campaign themes.

Former Vice President Joe Biden had a smaller but still vocal backing.

Vermont Sen. Bernie Sanders didn't bring supporters to the Liberty and Justice Celebration, keeping with his campaign's recent tradition of organizing an alternative event instead -- this time a "March to End Corporate Greed" early Friday evening. But Sanders, the only candidate to use a podium, arrived with an olive branch, saying his campaign had donated $20,000 to the Iowa Democratic Party.

Focus stays on Trump...

Nothing warms up a crowd of thousands of Democrats more than aggressively hitting President Donald Trump, and nearly every candidate on the stage used their platform to do just that.

Biden said he would beat the president "like a drum" and that Trump "knows it" because he has spent "a lot of money to make sure I'm not" the nominee.

"You give hate a little oxygen and it comes out from under the rocks," Biden said. "Well, he's breathed oxygen into hate."

Buttigieg labeled Trump a "divider-in-chief," arguing he is offering a White House "you can look at in the news and feel your blood pressure go down a little bit than up through the roof."

"This country cannot afford four more years of Donald Trump, we will not recognize it if he gets reelected," Buttigieg said, before adding he doesn't need "to throw myself a military parade to see what a convoy looks like. Because I was driving one in Afghanistan right around the time this president was taping season seven of the Apprentice."

Sanders labeled Trump a man "who does not understand the rule of law or our constitution."

Trump is "a man who will soon be impeached," he said.

These lines were clear crowd pleasers, winning polite applause from those in attendance supporting other candidates and raucous cheers from their respective supporters.

... But some Democrats focus on their opponents

The comments that got more attention, however, were the riskier lines where Democrats took on Democrats, some of whom shared the stage mere minutes apart.

Warren was the most direct in her critiques of her rivals, telling the audience that some "think that running some vague campaign that nibbles around the edges is somehow safe, but if the most we can promise is business as usual after Donald Trump, then Democrats will lose."

Warren then took a subtle dig at candidates like Biden, Buttigieg and others who are offering more incremental change.

"We win when we offer solutions big enough to touch the problems that are in people's lives. Fear and complacency does not win elections. Hope and courage wins elections," she said, adding, "I'm not running some consultant-driven campaign with some vague ideas that are designed not to offend anyone. I'm running a campaign based on a lifetime of fighting for working families."

"This is a time of crisis. And media pundits, Washington insiders, even some people in our own party don't want to admit it. They think that running some vague campaign that nibbles around the edges is somehow safe," she said.

But Warren, who has risen to front-runner status in recent months, also took some indirect criticism.

Harris highlighted her career as a prosecutor and then used that experience to subtly hit Warren.

"I have only had one client my entire life and that is the people. Unlike others, I have never represented a corporation," Harris said, a nod to Warren's previous work representing corporations.

Harris' high-pressure moment

Harris has had a very bad week.

Faced with struggling poll numbers and a cash crisis, Harris' campaign announced this week that the California Democrat was laying off staff at her Baltimore headquarters and all but shuttered her campaign in New Hampshire to fund a strategy that stakes her entire campaign on Iowa.

Harris stepped onto the stage here in Des Moines with more pressure than almost any of her speeches to date.

"This is a moment where we have to be prepared to fight for the best of our country," Harris said. "This is a moment where we need to fight for this country we love, for the rule of law, for our system of justice and for our very Democracy."

While thematically similar to the one she delivers on the campaign trail every day, her speech on Friday was more direct and pointed than her usual stump address.

The speech couldn't have come at a more important time for the senator, either. The audience at the Liberty and Justice Celebration on Friday night was -- by far -- the largest audience of Iowans Harris would address between now and the caucus.

Harries tried to seize on the Senate fights that initially helped propel her campaign.

Being a United States senator "meant taking on Jeff Sessions, taking on Bill Barr, taking on Brett Kavanaugh," Harris said, mentioning many of the Trump administration confirmation fights where she played a central role. "And Iowa, I stand before you today, for the people, fully prepared to take on Donald Trump."

The Andrew Yang Experience

Andrew Yang, who had never run for office before launching his 2020 Democratic presidential bid, joked during his speech that he is "barely a politician."

But that's not really true anymore.

The entrepreneur's campaign's animating cause is his "freedom dividend" -- a proposal to combat the threat automation poses to jobs by giving every American a universal basic income of $1,000 per month.

On Friday, Yang did what experienced politicians do: He told human stories. His campaign is running its own pilot program of sorts, and Yang talked about three people who are already receiving $1,000 per month. One man bought a guitar and is happier, playing shows for the first time in a long time. A woman paid for car repairs. A 68-year-old woman is going back to school. It was a deft touch for someone who early in his candidacy often looked out of place among the other Democratic presidential hopefuls.

The evening was a perfect window into what's become the Andrew Yang experience: Without fail, supporters of other candidates leave Democratic events saying that -- while they might not vote for him -- they liked hearing from Yang. Iowa's Democratic glitterati, the donors and officials seated around the stage, watched Yang's devoted following up in the stands stick with him through every word of a complicated call-and-response.

"I am running for president because, like so many of you in this room, I'm a parent and I'm a patriot," Yang said. "I have seen the future that lies ahead for our children, and it is not something I'm willing to accept."

Beto's exit

The most disappointed attendees Friday night were those who were there -- in some cases after traveling across the country -- to support Beto O'Rourke.

The former Texas congressman announced his departure from the 2020 race hours before the Liberty and Justice Celebration began. The news left supporters who had gathered just outside the Wells Fargo Arena for a pre-event rally crestfallen. Organizers quickly pulled up and stacked the black-and-white "Beto" signs that were mixed in with other candidates' throughout downtown Des Moines.

O'Rourke spoke to those supporters, and then Iowa Democratic Party Chairman Troy Price told the crowd inside the arena that the former lawmaker wouldn't be speaking Friday night.

Still, he did get some shout-outs from other candidates -- first Harris, then Sanders.

"I want to thank my good friend Beto O'Rourke for helping to lead the effort to end the horrific level of gun violence we see in this country," Sanders said.

Yang told reporters he was sad to see O'Rourke drop out because the El Pasoan "is someone I genuinely enjoyed spending time with."

The weak second half

The 13 Democratic candidates who spoke Friday were divided into two halves: The seven top-polling contenders, who spoke first, followed by an intermission in which several Iowa Democratic officeholders took the stage, and then the six lower-polling candidates to close out the night.

That set-up was bad news for the final six Democrats to speak.

More than half the crowd -- those who were there to hear from Buttigieg, Warren, Biden, Sanders, Harris or Tom Steyer -- headed for the exits at intermission. (Yang's supporters mostly stayed around.)

Booker and Minnesota Sen. Amy Klobuchar suffered the most.

Unlike the longest shots in the race, both are running campaigns with talented staff and organizational prowess. Both are polling in the low single digits, but have seen limited signs of momentum in recent weeks. And both delivered strong speeches that were heard in person by far fewer people than the top candidates reached.

Virtually no one stayed through the final two speakers of the night, former Maryland Rep. John Delaney and Montana Gov. Steve Bullock. Wait staff were pulling tablecloths off tables while Delaney was still speaking. The announcer lost her place before Bullock spoke, wrongly telling the crowd to "please welcome to the stage Sen. Cory Booker" rather than introducing the Montana governor.

The most memorable portion of Klobuchar's speech was the consistent low roar of a horn a supporter had brought.

"I think that's a Viking horn," she said. "You're gonna piss off all the Packer fans."