Nineteen presidents-in-waiting got five minutes apiece to address Iowa Democrats from a single stage on Sunday, seizing the chance to make a splash and stand out from a pack of two dozen who want their party's nomination.

The front-runner is marching to his own cadence, however: Former Vice President Joe Biden wasn't in the eastern Iowa town of Cedar Rapids to lock horns with the other polling leaders. He chose to attend his granddaughter's high school graduation instead.

Sunday's event, what political insiders describe as a 'cattle call,' was the first official one of its kind in the 2020 campaign season.

The high-profile audition came as Democratic White House hopefuls are jockeying for position on abortion rights, economic inequality, global warming, health care, gun control and foreign policy, and hoping to catch a gust of populist wind in their sails.

They all agreed that President Donald Trump can't be allowed to have a second term in office.

'I'm running for president because we can't take four more years of Donald Trump!' said New Jersey Sen. Cory Booker.

Nineteen of the 24 declared Democratic presidential candidates descended on Cedar Rapids, Iowa on Sunday for the opportunity to speak to Iowa Democratic Party insiders for five minutes apiece

Vermont Sen. Bernie Sanders said Donald Trump is 'the most dangerous President of the United States in American history'

Former Vice President Joe Biden's absence was felt Sunday; he's trying to avoid sharing his front-runner status with his rivals by appearing with them

President Donald Trump awaits a challenger and has said he doesn't care who he faces in 2020, but Democrats are eager to make sure he doesn't get a second term in office

Trump, said Vermont Sen. Bernie Sanders, is 'the most dangerous President of the United States in American history.' But he acknowledged the dynamic presence that has allowed Trump to monopolize the nation's attention on nearly every issue.

'We will not defeat Donald Trump unless we bring excitement and energy into this campaign,' he warned.

Pushing the bounds of his allotted five minutes, Sanders found himself in the role of a long-winded Oscar winner fighting 'play-off' music as he thanked the third tier of his helpmates.

His final plea to 'finally put an end to sexism, racism, homophobia and religious bigotry' went largely unheard as music covered him.

But his audienced snapped to attention at his description of the Trump presidency, which was the day's starkest and most unvarnished.

'The American people do not want a president who is a pathological liar, a racist, a sexist, a homophobe, a xenophobe, a religious bigot and someone who believes that he is above the law.'

Massachusetts Sen. Elizabeth Warren, whose stock is climbing in Iowa, emphasized her decision to organize around small-dollar donors and take selfie after selfie with them.

'I'm coming up on my 30,000th selfie. That's how you build a grassroots movement,' she said.

'I'm not spending my time with high-dollar donors and with corporate lobbyists. I'm spending my time with you.'

Dueling masses of humanity like this group of Kamala Harris supporters yelled slogans and beat tambourines outside the Cedar Rapids, Iowa convention center on Sunday

South Bend, Indiana Mayor Pete Buttigieg spoke about Democrats' need to reclaim the mantles of 'freedom' and 'patriotism' from Republicans, and said God doesn't belong to a political party – 'least of all the one that produced this current president'

California Sen. Kamala Harris, a former prosecutor, said Trump has committee a series of 'frauds,' including the 'identity fraud' of claiming to be the best president in a generation – when that distinction belongs to Barack Obama.

Trump 'has defrauded the American people,' she snapped, and 'we need to prosecute the case.'

'There's a rap sheet full of evidence,' Harris said.

Minnesota Sen. Amy Klobuchar's jab at Trump was more playful than most, slapping back at his criticism of her campaign launch event, a snow-swept tableau that left her careful coiffure wet and crunchy.

The president at the time cracked a joke about global warming.

'Hey Donald Trump,' Klobuchar said Sunday, 'the science is on my side and I'd like to see how your hair would fare in a blizzard.'

Washington state Gov. Jay Inslee emerged as the afternoon's most energetic climate warrrior, saying the Earth is nearing the point of no return and faces an 'existential threat' from carbon emissions.

'This is our last chance to save this nation from this urgent and imminent cataclysm,' he said to polite but tepid applause. 'We understand that there will not be another chance.'

Pete Buttigieg, the South Bend, Indiana mayor who hopes to be America's first openly gay president, spoke derisively of Trump's ability to maintain a grip on the nation's political attention.

California Sen. Kamala Harris, a former prosecutor, claimed Trump has committee a series of 'frauds,' including the 'identity fraud' of claiming to be the best president in a generation – when that distinction belongs to Barack Obama

New York City Mayor Bill de Blasio told Iowa Democrats that 'there's plenty of money in this country' to accomplish his ambitious government agenda, but 'it's just in the wrong hands'; de Blasio became the first New York mayor in decades to skip Sunday's Puerto Rican Day parade, campaigning in Iowa instead

'The only thing we can do is to look at the show that this president has created… and we are going to change the channel to something completely different,' he pleaded. 'Help me change the channel.'

In a more substantive five-minute oration than most, he said Americans should embrace popular-vote presidential elections, demand steep minimum-wage increases and lean toward statehood for Puerto Rico and the District of Columbia.

'Freedom includes economic freedom, and you're not free if you don't have a living wage in this country,' he said.

Buttigieg blasted Trump for promoting a 'vision of security [that] goes no further than putting up a wall from sea to shining sea.'

That, he said, ignores 'the violent white nationalism that presents a clear and present threat to our country.'

And in a veiled slap at Republicans' longstanding alliance with evangelical groups that condemn his wedded-gay lifestyle, Buttigieg glared at cameras and declared: 'God does not belong to any political party, least of all the one that produced this current president.'

Buttigieg, an amateur pianist, walked to the convention center after playing keyboard onstage with a hired band at a 'Picnic with Pete' event at a nearby park.

Looking out at food trucks and a face-painting station, the 37-year-old military veteran said Americans are ready for a millennial president. He also touted his short political career as mayor of a midwest city.

'Washington needs to start working more like our best run cities instead of the other way around,' Buttigieg told a cheering crowd of about 400.

Until Buttigieg and his husband became the American political media's new 'it' couple, former Texas Rep. Beto O'Rourke occupied the John F. Kennedy slot in the primary field: young, handsome, daring and different.

Poll numbers released Saturday, however, put his support among Iowa caucus-goers at an anemic 2 per cent.

Speaking last on Sunday's program, O'Rourke spelled out a substantial agenda including veterans health care, abortion rights, gun control and voting reform.

Kirsten Gillibrand, a New York U.S. senator, said she can beat the president in 2020: 'Trump's Kryptonite is a strong woman who stands up for what she believes in'

Massachusetts Sen. Elizabeth Warren boasted on Sunday that she was nearing her 30,000th selfie on the trail, saying that one-on-one retail campaigning will be her path to victory

Former Texas Democratic Rep. Beto O'Rourke spoke last on Sunday's program and pledged that as president he would end the 'carnage and bloodshed' caused by 'weapons of war' sold to American gun owners

He blasted past presidents for pursuing 'this country's foreign policy goals on the backs of 19, 20, 21-year-old old women and men,' and called for the end of foreign military adventurism.

O'Rourke pledged that as president he would end the 'carnage and bloodshed' caused by 'weapons of war,' referring to AR-15 and other similar military-style rifles.

And he demanded 'same-day and automatic voter registration' to enlarge the base of ballot-casters, calling for an end to 'purges of the voter rolls and voter IDs.'

O'Rourke said Sunday morning on ABC's 'This Week' program that President Trump 'has yet to be brought to justice' for 'potential crimes' he committed during the 2016 campaign and in the years since.

'Those crimes,' he claiomed, 'might extend beyond what we've seen in the Mueller report.'

Kirsten Gillibrand, a New York senator, devoted her Sunday speech to promoting the idea of a woman serving in the Oval Office.

'Right-wing politicians and a whole lot of men,' she complained, are working to restrict abortion rights. 'Now is not the time to be polite,' she said. 'Now is not the time for small steps. Now is the time to fight like hell.'

'President Trump's Kryptonite is a strong woman who stands up for what she believes in,' she said in a halting, at times nervous-sounding address.

AGES OF THE 2020 CANDIDATES ON INAUGURATION DAY As of April 8, 2020 there were two major party candidates in the 2020 presidential election. Here is the age each of them would be on Inauguration Day 2021 if he were to win: Former Vice President Joe Biden (D) : 78 years, 2 months, 1 day

: 78 years, 2 months, 1 day President Donald Trump (R) : 74 years, 7 months, 7 days Advertisement

Candidates handed out swag to their fans on Sunday, including 'persist' cookies from Elizabeth Warren and light-up campaign signs from Cory Booker

Presidential candidate Pete Buttigieg hosted a picnic in Cedar Rapids on Sunday, handing out signs that mocked Trump's purposeful mispronunciation of his last name

Iowa is the first U.S. state where voters in the primary season choose who to nominate for the presidency. Its February 3, 2020 caucuses will be the starting gun for a race that won't end until Election Day.

Unlike a traditional primary election, caucus votes are conducted after a series of speeches that differ from one precinct to the next but all take place at the same time across Iowa.

New Hampshire's primary election will take place eight days later, and is the first of its kind every four years.

Sunday's event in Cedar Rapids was an opportunity for Democratic candidates to stand out from the crowd and impress donors, organizers and potential high-profile endorsers.

The street outside the Cedar Rapids Convention Center on Sunday looked more like a cheerleading competition than political ground zero on Sunday morning, with rival groups of volunteers chanting their heroes' names at passing cars and rubbernecking TV cameras.

Booker's supporters blasted 'Born to Run,' a high-octane American anthem from the Garden State's favorite son Bruce Springsteen.

Klobuchar's team countered with an ear-splitting playlist from the late Twin Cities star Prince.

And in the summer heat, California Sen. Kamala Harris' backers banged on drums and tambourines while they chanted her first name in a swelling staccato.

Her supporters and Kirsten Gillibrand's, facing off across the street, joined in a chant before the afternoon's speech began.

'It's time! It's time! It's time for a woman in the White House!' they yelled, with drums and cowbells keeping time.

Biden spent Sunday outside the Hawkeye State but will make four campaign stops on Tuesday, hours before President Donald Trump speaks at a nighttime fundraiser for the Republican Party of Iowa.

Buttigieg met with supporters outdoors while his competitors were rallying on street corners downtown

New Jersey Sen. Cory Booker said Sunday the Democratic Party 'doesn't need a savior - we need each other'

All the candidates from the first tier that emerged in poll results released Saturday were on the program, along with many who appear to have a slim chance of catching fire.

New York City Mayor Bill de Blasio complained that 'a lot of people feel there's more stress in our lives,' and claimed it's 'not an accident.'

'It was a Republican agenda that made it harder and harder for the poor to get their fair share, and made it easier and easier for the rich to get richer,' he said.

De Blasio, a socialist warrior whose electoral success in New York City faces a tough test in less liberal parts of the country, told Iowa Democrats that he could accomplish his ambitious but costly agenda through a shaking of America's economic Etch-a-Sketch.

'There's plenty of money in this country. It's just in the wrong hands,' he said.

Booker said the Democratic Party 'doesn't need a savior – we need each other.'

'This is a moral moment in America and we must meet this test,' he said.

'I'm running for President to beat Donald Trump and I'm running for President because beating Donald Trump is not enough. We must have bigger aspirations and bolder dreams than just that,' he boomed in his five-minute soliloquy.

'Beating Donald Trump is the floor. It is not the ceiling. Beating him will get us out of the valley, but it will not get us to the mountaintop.'

Booker's supporters waved signs trimmed with Christmas tree lights, pre-set on their tables, as they shouted 'Cory! Cory! Cory!'

Massachusetts Sen. Elizabeth Warren's fans got cookies iced with her tag line: 'Persist.' Klobuchar's backers found copies of her campaign-year book at their places.