AUSTIN, Texas — Former Obama housing secretary Julián Castro, the only Latino in the 2020 Democratic presidential primary race, on Thursday ended his campaign that had pushed the field on immigration and swung hard at rivals on the debate stage but never found a foothold to climb from the back of the pack.

“I’m so proud of the campaign we’ve run together. We’ve shaped the conversation on so many important issues in this race, stood up for the most vulnerable people and given a voice to those who are often forgotten,” Castro said in an online video. “But with only a month until the Iowa caucuses, and given the circumstances of this campaign season, I have determined that it simply isn’t our time.”

The video continues, “So today it’s with a heavy heart and with profound gratitude that I will suspend my campaign for president. To all who have been inspired by our campaign, especially our young people, keep reaching for your dreams — and keep fighting for what you believe in.” 

Castro, who launched his campaign in January, dropped out after failing to garner enough support in the polls or donations to make recent Democratic debates. A former San Antonio mayor who later became President Barack Obama’s secretary of Housing and Urban Development, Castro had stalled for most of his campaign around 1% in polls and never came close to raising money like his better-known rivals.

He had not yet released his end-of-year fundraising totals, but by October he had raised less than $8 million total. As Castro exited the field, Bernie Sanders announced on Thursday that he brought in more than $34.5 million in the previous three months alone. 

Castro’s exit reflects the increasing lack of color in a Democratic field that began as one of the most diverse in history. Between Sen. Kamala Harris of California dropping out and Sen. Cory Booker of New Jersey also lagging, the sixth and final Democratic debate of 2019 had no black or Latino candidates on stage. 

Castro expressed disappointment and concern about the growing lack of diversity, and in Iowa he ran an ad arguing that the state should no longer go first in Democrats’ nominating process because it doesn’t reflect the diversity of the Democratic Party.

Castro, 45, was among the youngest in the running at a moment when the party’s ascendant left wing is demanding generational change. And as the grandson of a Mexican immigrant, Castro said he recognized the meaning of his candidacy in the face of President Donald Trump’s inflammatory anti-immigrant rhetoric and hardline policies on the U.S.-Mexico border.

But he labored not to be pigeonholed as a single-issue candidate. He made the attention-getting choice of Puerto Rico as his first campaign stop, recited the names of black victims killed in high-profile police shootings and was the first in the field to call for Trump’s impeachment. He also was a leading voice in he field on poverty and ending hunger. 

But his sagging poll numbers never budged. Early on, he was often eclipsed by another Texan in the race who dropped out this fall, former Rep. Beto O’Rourke, and another young former mayor, Pete Buttigieg of South Bend, Indiana. His campaign and supporters, meanwhile, grumbled that he didn’t get due credit for taking out-front positions. 

Warren was among the first in the field to react to Castro’s departure, tweeting, “Thank you @JulianCastro for being a powerful voice, for proposing bold and progressive plans, and for using your campaign to help people who need it now.”

Trying to show he could go toe-to-toe with Trump, Castro swung for big moments on debate stages, and he 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.

Castro was pegged as a rising Democratic star after being elected as mayor of the nation’s seventh-largest city at age 34, and he was on the short list for Hillary Clinton’s running mate in 2016. 

In the video announcing his exit, Castro concludes with “¡Ganaremos un día!” — which translates to “We will win one day!”