Former Rep. Beto O’Rourke (D-TX) is ending his presidential campaign after struggling for months to gain momentum, as the crowded Democratic primary thins out less than 100 days before the Iowa caucus.

“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 a Medium post announcing his move on Friday.

“My service to the country will not be as a candidate or as the nominee. Acknowledging this now is in the best interests of those in the campaign; it is in the best interests of this party as we seek to unify around a nominee; and it is in the best interests of the country.”

Rumors about O’Rourke’s candidacy began shortly after his Senate campaign concluded. But for months, he put off making a decision, leaving top Democratic operatives who may have signed on with him to look elsewhere. The entrance into the race of South Bend Mayor Pete Buttigieg, perceived to occupy the same lane for a young, fresh-faced outsider, appeared to further dull the allure of O’Rourke’s bid.

When he finally launched he did so with much fanfare. A Vanity Fair article timed to his announcement marketed his bid as a second chance at political greatness for the former Texas congressman after failing to unseat Republican Sen. Ted Cruz.

O’Rourke was featured on the magazine cover standing on a dirt road, outside a pick-up truck with the words, “Beto’s Choice” written in bold over his left shoulder and the quote, “I want to be in it. Man, I was born to be in it.”

And he was, for a few weeks, anyway.

In the first 18 days of his candidacy, O’Rourke raised an impressive $9.4 million. But his star began to fall as quickly as it rose. A lack of fully formed policy positions and a series of lackluster debate appearances contributed to his failure to harness the same energy that that was seen during his Senate campaign.

A mass shooting at a Walmart in his hometown of El Paso took him off the campaign trail briefly in August as he mourned with his community.

When he returned to the race, O’Rourke, 47, called for a mandatory buyback program of assault-style weapons, which ignited loud applause during a Democratic primary debate in his native Texas in September. Days later, his unofficial campaign slogan became “hell yes”—a line from his debate performance that if he were elected president, he would buy back such weapons.

While the move helped rally some progressives in key voting states, his promise proved to be politically risky and was met with some skepticism among his fellow Democrats and guns rights activists, who argued he was giving fuel to Republicans by calling for such drastic measures.

By the end of his campaign, O’Rourke was at approximately 2 percent nationally. And while he made his plans to withdraw from the presidential race public on Friday, he has consistently ruled out running for any other office in 2020, including challenging Sen. John Cornyn (R-TX).

“Oh no, Beto just dropped out of race for President despite him saying he was “born for this.” I don’t think so!,” President Donald Trump tweeted on Friday afternoon.

Just hours before he suspended his bid, his campaign released official plans to file for the New Hampshire primary and return to the state on Nov. 8. “Beto will be joined by local supporters at the New Hampshire State House for the filing event,” the release reads.

Ultimately, O’Rourke pledged to help elect the party’s nominee to take on Trump in the general election. “We will work to ensure that the Democratic nominee is successful in defeating Donald Trump in 2020,” he wrote.

“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.”