Beto O'Rourke is dropping out of the 2020 presidential race

Democratic presidential candidate and former Rep. for Texas Beto O'Rourke speaks at the Iowa Federation Labor Convention on August 21, 2019 in Altoona, Iowa.

Joshua Lott | Getty Images

Former Texas Senate candidate Beto O'Rourke said Friday that he will drop out of the 2020 presidential race, making him the latest candidate to exit the still-crowded but narrowing Democratic primary contest.

"Our campaign has always been about seeing clearly, speaking honestly, and acting decisively," O'Rourke announced in a series of tweets. "In that spirit: I am announcing that my service to the country will not be as a candidate or as the nominee."

The announcement also included a link to a lengthy post on Medium, in which O'Rourke vowed to support the eventual Democratic nominee.

"We will work to ensure that the Democratic nominee is successful in defeating Donald Trump in 2020," O'Rourke wrote in the blog post. "I can tell you firsthand from having the chance to know the candidates, we will be well served by any one of them, and I'm going to be proud to support whoever that nominee is."

O'Rourke had told some of his donors earlier this week that he was likely going to drop out, people familiar with the matter told CNBC.

Mark Gallogly, the founder of investment firm Centerbridge Partners and a lead bundler for O'Rourke, told CNBC that "Beto consistently raised important issues with great integrity and energy for all Americans."

O'Rourke, 47, was a U.S. representative from Texas before giving up his seat to run for Senate in 2018 against incumbent Sen. Ted Cruz. His impressive fundraising numbers and large crowds in that race garnered national attention, raising hopes among Democrats that Texas, traditionally a reliably Republican stronghold, could be turned blue.

Despite losing to Cruz, O'Rourke announced in March that he would run for president. But his national campaign was rarely able to match the enthusiasm he generated in Texas.

The RealClearPolitics polling average never showed O'Rourke cracking 10% in the polls, and his popularity appeared to trend downward as the Democratic primary wore on.

His campaign's fundraising numbers also fell well below the front-runners in the primary: He posted $4.5 million in the most recent quarter, compared with Vermont Sen. Bernie Sanders' $25.3 million and Massachusetts Sen. Elizabeth Warren's $24.6 million in the same period.

"Though it is difficult to accept, it is clear to me now that this campaign does not have the means to move forward successfully," O'Rourke wrote in his Medium post.

President Donald Trump, who was traveling to Mississippi for a campaign rally, taunted O'Rourke in a tweet.

"Oh no, Beto just dropped out of race for President despite him saying he was 'born for this.' I don't think so!" Trump tweeted, referring to a quote from a profile in Vanity Fair, in which O'Rourke said he was "just born to be in" the race for the White House.

O'Rourke emerged as the most hard-line gun control advocate in the field in August, following a deadly mass shooting at a Walmart in his hometown of El Paso, Texas, that left 22 dead and dozens injured.

O'Rourke was scorned by Republicans for his defiant stance on confiscating AR-15 rifles, which have become associated with mass shootings in the U.S.

"Hell yes, we're going to take your AR-15, your AK-47," he said during a primary debate in September.

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