Beto O'Rourke says he will seek the Democratic nomination for president in 2020.

The decision comes after months of questioning whether to run, a road trip, and mostly avoiding media appearances.

O'Rourke's entrance into the race adds one of the most prolific fundraisers of the past midterm election cycle.

WASHINGTON — The Democratic former Texas congressman Beto O'Rourke is seeking the Democratic nomination for president in 2020, he announced in a video Thursday morning.

O'Rourke appeared in the video, released at 6 a.m. ET, alongside his wife, Amy. He described the 2020 election as the "defining moment of truth" for the US.

"Amy and I are happy to share with you that I'm running to serve you as the next president of the United States of America," he said.

"The challenges we face right now, the interconnected crises in our economy, our democracy, and our climate, have never been greater, and they will either consume us or they will afford us the greatest ever opportunity to unleash the genius of the USA.

"We are truly now, more than ever, the last great hope of Earth. At this moment of maximum peril and maximum potential, let's show ourselves, and those who will succeed us in this great country, just who we are and what we can do."

Former Rep. Beto O'Rourke (D-Texas) PAUL RATJE/AFP/Getty Images

The day before his announcement, Vanity Fair magazine published a long profile of O'Rourke, in which he said "I want to be in it," referring to the 2020 race.

"Man, I'm just born to be in it, and want to do everything I humanly can for this country at this moment," he said.

While candidates have been entering the race on an almost weekly basis for much of this year, O'Rourke took it slow, going on a solo road trip around parts of the United States and mostly avoiding national media.

Earlier this week, INSIDER reported that O'Rourke was running paid Facebook ads promoting his campaign website and noting that he had made a decision.

"People in communities across the country have been reaching out and asking me if I'm planning on running in 2020," the ads said. "Amy and I have made a decision on that. Sign up today to be first to know what's next. I'd like for you to be a part of it."

Before announcing his run, O'Rourke drew national attention for a large rally and march through the streets of El Paso, Texas. The demonstration occurred at the same time President Donald Trump held a campaign-style rally across town.

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Trump had been rallying his supporters to back construction of a border wall, which culminated in the announcement of a national-emergency declaration meant to divert military funds for physical barriers along the border. But O'Rourke's rally demonstrated that he could still whip up an enthusiastic crowd and lead supporters for a particular cause.

O'Rourke's entrance into the race adds one of the most prolific fundraisers into an increasingly crowded field of candidates. During his unsuccessful 2018 Senate campaign to unseat the incumbent Republican Ted Cruz, O'Rourke amassed nearly $40 million in donations in a single quarter and refused money from corporate PACs.

Shortly after the 2018 election, O'Rourke did not fade from public view, as Democratic groups invited him to visit Iowa and New Hampshire, as is customary for aspiring presidential candidates.

From 2013 until this year, O'Rourke represented Texas' 16th Congressional District, which contains El Paso. While in Congress, O'Rourke was a member of the New Democrat Coalition, which serves as a working group for more moderate members of the House Democratic Caucus. O'Rourke also served on the Veterans' Affairs and Armed Services committees.

But O'Rourke has also drawn a harsher tone when discussing Trump, calling for his impeachment after the 2018 summit with Russian President Vladimir Putin in Helsinki.

"Standing onstage in another country with the leader of another country who wants to and has sought to undermine this country, and to side with him over the United States — if I were asked to vote on this, I would vote to impeach the president," O'Rourke told The Dallas Morning News.

He later backtracked the comments, saying that first Congress should "allow the Bob Mueller investigation to follow its course, and allow him to find the facts wherever they lead, as high up as they go."

"On the issue of impeachment, I've never called for it, and you've seen us, I've never led a town hall with it," he said. "I’m not on the resolution calling for the president's impeachment."