Beto O'Rourke, the former Texas congressman, announced Friday that he was ending his Democratic presidential campaign, which failed to recapture the enthusiasm, interest and fundraising prowess of his 2018 Senate race.

In an online post, O'Rourke said, "My service to the country will not be as a candidate or as the nominee." He was scheduled to address supporters later Friday at an event in Iowa.

O'Rourke was urged to run for president by many Democrats who were energized by his narrow Senate loss last year in Texas, a reliably Republican state. He raised an astonishing amount of money from small donors across the country, visited every county in Texas and used social media and livestreaming video to engage directly with voters. He ultimately lost to incumbent Republican Sen. Ted Cruz by 3 percentage points.

But O'Rourke struggled to replicate that model in the presidential primary and both his polling and his fundraising dwindled significantly in recent months.

"Though it is difficult to accept, it is clear to me now that this campaign does not have the means to move forward successfully," he wrote on Medium. "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."