Longshot Democrat presidential candidate Julián Castro ended his flailing White House campaign on Thursday after struggling to achieve a breakthrough in the polls in a crowded Democrat primary field.

“Today, it’s with a heavy heart and profound gratitude that I will suspend my campaign for president,” Castro said in a video statement shared to Twitter, adding it “simply isn’t our time” to clinch the Democrat nomination. “I’m so proud of everything we’ve accomplished together. I’m going to keep fighting for an America where everyone counts—I hope you’ll join me in that fight,” he added.

It’s with profound gratitude to all of our supporters that I suspend my campaign for president today. I’m so proud of everything we’ve accomplished together. I’m going to keep fighting for an America where everyone counts—I hope you’ll join me in that fight. pic.twitter.com/jXQLJa3AdC — Julián Castro (@JulianCastro) January 2, 2020

Castro, the sole Latino to mount a bid for the White House this cycle, was hampered for months by poor fundraising, and failed to qualify for the most recent Democrat presidential primary debate in Los Angeles, California. While he ran an overtly progressive campaign, championing far-left positions on issues such as immigration, his candidacy was often overshadowed by rivals like former Rep. Robert Francis “Beto” O’Rourke (D-TX) and former South Bend, Indiana, Mayor, Pete Buttigieg (D).

Trying to show he could go to-to-toe with Trump, Castro swung for big moments on debate stages, and flirted with a much-needed breakout in June after confronting O’Rourke over not supporting decriminalization of illegal border crossings.

But turning his sights on Biden on a later stage brought swift backlash. During the September debate in Houston, Castro appeared to touch on concerns about the age of the then-76-year-old former vice president and added a parting shot at him.

“I’m fulfilling the legacy of Barack Obama, and you’re not,” Castro said.

Castro — who was Obama’s housing secretary in his second term — denied taking a personal dig at Biden as others in the field condemned the exchange. Three days later, Castro lost one of his three backers in Congress, Rep. Vicente González of Texas, who switched his endorsement to Biden.

Castro had warned supporters in a fundraising appeal that failing to make the November debate stage would spell the end of his campaign. He needed to hit at least 3% polling in four early state or national polls but didn’t get even one.

What is next for Castro is unclear. Back home in Texas, Democrats had long viewed Castro as their biggest star in waiting and some have urged him to run for governor as the state trends more diverse and liberal.

The Associated Press contributed to this report.