KEOKUK, Iowa — Newly announced presidential candidate Beto O’Rourke launched the first event of his 2020 campaign on Thursday with an appeal to his fellow Democratic hopefuls not to descend into divisiveness as they attempt to oust President Donald Trump from office.

"Any single Democrat running today — and I may not be able to enumerate every single one of them — would be far better than the current occupant of the White House," O'Rourke, a Texas Democrat, told a packed coffee house. "So let's keep this in mind, and we can conduct ourselves in this way every single day for the next 11 months until voting begins here in Iowa."

“Ultimately, we all have to get on board with the same person, because it is fundamental to our chances of success that we defeat Donald Trump in 2020,” he said shortly after announcing his candidacy online.

O'Rourke nascent campaign tried to keep the details of his first-ever trip to Iowa secret to allow the former congressman to exercise his well-honed brand of retail politicking. But word leaked, and the tiny Lost Canvas coffee shop in this politically wired state was mobbed by the time O'Rourke arrived.

"They prefer it to be low key, like any normal day, but good luck with that, " quipped Mary Jo Riesberg, the co-chair of the local Democratic Party.

In the crush of the crowd, O'Rourke, who is 6-foot-4, shook hands, posed for selfies, and stooped to offer music recommendations. "Don't forget Blaze Foley," he said to one woman, referring to the obscure alt-country cult hero who was the subject of a recent Ethan Hawke-directed biopic.

Then he climbed atop a table, large coffee cup in hand, and took a litany of policy questions,saying the question-and-answer format of his first campaign stop is an example of how he wants to run his campaign.

"This is democracy, and in the spirit of that, I want to make sure that I have the chance to listen to you," O'Rourke said, adding: "If you want to pose the solution to your question, from your perspective, where you live, from how you see things, I am all ears right now. There's no sense in campaigning if you already know every single answer."

"I could care less your party persuasion, your religion, anything other than the fact that we are all Americans and we are all human being," he said.

He said there is an urgent need to fight climate change and take on corporate interests, endorsing the idea of a Green New Deal, and calling for “guaranteed high-quality health care" -- but notably not Medicare for All.

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He also repeated his call to legalize marijuana, telling the almost entirely white audience that the war on drugs has mostly hurt people that “do not look like people in this room.”

On his way out, he climbed behind the wheel of a black minivan to drive himself and his staff to his next event while conducting an interview with a local radio reporter.

The scene, and his packed schedule -- which included about a half-dozen stops on Thursday alone -- is an example of the relentless work ethic O'Rourke has brought to his campaigns, one that Democrats here say could help make him competitive in the state's first-in-the-nation caucus.

O’Rourke, who drew national attention and broke fundraising records with his losing campaign against Sen. Ted Cruz last year, announced his presidential run earlier Thursday, entering an already crowded primary field.

The 46-year-old former congressman from El Paso has captivated some in the party with his skateboarding, adventurous road trips shared on social media, but he has also attracted plenty of critics of all political stripes -- including the president of the United States.

"I think he has a lot of hand movement. I’ve never seen so much hand movement," President Donald Trump told reporters in the Oval Office on Thursday. "Is he crazy or is that just the way he acts?"

Former Texas congressman Beto O'Rourke speaks during a campaign stop in Burlington, Iowa, on March 14, 2019. Daniel Acker / Reuters

But O'Rourke also received some early signs of support.

At least three members of Congress issued almost immediate endorsements: Reps. Kathleen Rice, D-N.Y., Stephanie Murphy, D-Fla., and Veronica Escobar, D-Texas, who represents his old El Paso-based congressional district.

"I have endorsed Beto O’Rourke in every election he’s run, including this exciting run for President of the United States, because he is an extraordinary public servant, driven by compassion and a desire to unify," Escobar said.

And his campaign said it had raised money from all 50 states hours after his launch.

Draft Beto, a group formed to get the Texan into the 2020 race, declared victory and said they had built an email list of 30,000 names after holding more than 40 events in early primary and caucus states.

O'Rourke told Vanity Fair in a lengthy cover-story profile published Wednesday: "You can probably tell that I want to run. I do. I think I'd be good at it."

On Saturday, he'll rally with Eric Giddens, a Democrat running in next week's special election for an Iowa state Senate seat, who has received plenty of support from other 2020 Democratic hopefuls.

In narrowly losing to Cruz last year, O'Rourke won a national following and more votes than any Democrat in Texas history. He raked in a record $79 million, mostly from small-dollar donors, after rejecting all PAC money.

O'Rourke told NBC affiliate in Dallas-Forth Worth that his 2020 presidential campaign will be much like that 2018 Senate run, which he called “a campaign of people, not PACs.”

O'Rourke also said he decided to run after spending a lot of time with his family after his Senate campaign loss, and "really got to think long and hard about the future of our kids and, by extension, the future of this country. And when we looked out at that, there’s no sitting on the sidelines. There’s no hoping that somebody else can get this done. It’s all of us, all in, with everything that we've got for everyone."

The former punk rocker's Senate campaign drew comparisons to Barack Obama and Robert F. Kennedy, as celebrities and far-away Hollywood liberals fawned over everything from his skateboarding to his bold answer on NFL players kneeling to protesting police violence against African-Americans.

But as presidential speculation swelled after the November election, O'Rourke largely withdrew from the political scene, even as a dozen other Democrats jumped into the race to take on Trump.

Now, many in the party wonder if O'Rourke missed his moment. Others question how much of O'Rourke's national support last year was driven by liberals' animosity to Cruz, rather than genuine affection for O'Rourke.

And with the most diverse slate of presidential candidates in history, some Democrats have criticized the congressman for rising to a level they say would be unthinkable for a woman or person of color with a resume like his — only three terms in Congress and one losing Senate campaign.

A new documentary about his 2018 campaign premiered last weekend at the South by Southwest festival in Austin, Texas, and could help reignite the "Betomania" that swept bluer parts of America.

The large and growing Democratic field already includes Sens. Kamala Harris, Elizabeth Warren, Amy Klobuchar, Cory Booker and Bernie Sanders, and others like Washington Gov. Jay Inslee, former Colorado Gov. John Hickenlooper and ex-San Antonio Mayor Julian Castro, among others. And former Vice President Joe Biden is expected to announce soon whether he intends to jump in the race.