MUSCATINE — For months he’s looked like a candidate, stumped like a candidate, and even roadtripped like a candidate.

And as Beto O’Rourke told a house of supporters in Muscatine Thursday night, as of earlier Thursday he is finally a candidate for president.

And he’s already found his refrain: “We’re going to have to work together.”

“I want us to come together to unite. And it’s going to take all of us,” O’Rourke told the crowd of more than 100 people, squeezed into a small house that was packed to the elbows with press, voters and supporters. “Given the challenges we face, we will not overcome them with only half the country.”

After months of teasing a run to be the Democratic nominee, O’Rourke — or just “Beto” (BEH-toh) as supporters call him — launched his candidacy Thursday morning amid his first-ever trip to Iowa. He also released a kickoff video on social media.

O’Rourke is the 46-year-old former congressman from El Paso, Tex., whose political star rose last fall when he ran for Senate and nearly unseated Sen. Ted Cruz (R-TX). O’Rourke lost the race but became something of a Democratic celebrity, racking up endorsements from LeBron James, Eva Longoria, and Beyoncé.

If elected, O’Rourke would be the first person to go from the House to the presidency since James Garfield, in 1880.

On Thursday night, O’Rourke discussed several major issues for Democratic candidates: health care (O’Rourke has indicated interest in universal care), climate change (which he called “the ultimate existential threat”), and threats to democratic participation (O’Rourke has vocally championed House Bill 1, a comprehensive bill passed this month by the Democratic House to tackle financing and ethics in government).

After his brief stump speech, perched atop a small stool, O’Rourke took questions from the crowd. He seemed comfortable in front of the crowd, speaking loudly in a blue button-down under a grey sweater, which he eventually took off as the room grew warmer.

“The great news for our democracy is that there are so many people who are willing to step up, including those here,” O’Rourke said, “because they recognize that this is a defining moment of truth for this country.”

Voters in attendance expressed their interest in meeting O’Rourke, whose celebrity preceded him. The excitement over O’Rourke reminded Dorothy Riley, an 84-year-old Iowan, of when she saw John F. Kennedy campaign in Moline almost 60 years ago.

The 2018 Texas senate race, decided by less than 3 percentage points, was marked by unprecedented turnout and enthusiasm, particularly among young voters and minorities. O’Rourke, known for his social media savvy and fundraising, received more than twice as many votes as the Democratic nominee in the 2014 Texas Senate race.

O’Rourke came to Iowa this week to stump for Eric Giddens, of Cedar Falls, a Democrat running for state Senate in a special election. On Thursday O’Rourke stopped in Keokuk, Fort Madison, and Burlington before ending his day at the Muscatine event.

He plans to spend at least two more days traveling through the eastern part of the state, including stops in Cedar Rapids, Waterloo, and Dubuque.

“I don’t want us to be defined by our differences or our divisions,” O’Rourke said. “I never denigrate or put down. I always seek to lift up and bring out the very best, because people bring out the very best in me.”