Julian Castro, a former member of Barack Obama's cabinet, has joined the 2020 presidential race as the rush of Democrats making early moves to challenge Donald Trump accelerates.
"I'm running for president because it's time for new leadership, because it's time for new energy and it's time for a new commitment to make sure that the opportunities that I've had are available to every American," Mr Castro told cheering supporters.
Mr Castro, who could end up being the only Latino in what is shaping up to be a crowded Democratic field, officially kicked off his campaign with a rally in his home town of San Antonio, where he was mayor for five years.
The ex-housing secretary became the second Democrat to formally enter race, after former Maryland representative John Delaney.
Senator Elizabeth Warren of Massachusetts has also started an exploratory committee for president, and four other Democratic senators are taking steady steps toward running. Hawaii Representative Tulsi Gabbard, the first Hindu elected to Congress, is planning a bid too.
Mr Castro, the 44-year-old grandson of a Mexican immigrant, made the campaign announcement at Plaza Guadalupe, less than 200 miles from the US-Mexico border.
The impasse over a border wall that Mr Trump made a central promise of his 2016 campaign has led to the longest government shutdown in US history.
Joining Mr Castro at the campaign kick-off was his twin brother, Democratic Representative Joaquin Castro, chairman of the Hispanic congressional caucus and a frequent Trump critic.
“We’re going to make sure that the promise of America is available to everyone in this 21st century." Former secretary of Housing and Urban Development Julián Castro, a Democrat, announces his 2020 presidential bid in San Antonio, where he served as mayor. https://t.co/hfFA5ElyUk pic.twitter.com/yY4khcWkkg— CNN (@CNN) January 12, 2019
The Democratic field is starting to take shape even though the first primary elections are more than a year away.
Senator Kamala Harris of California has recently published a memoir, a staple of presidential candidates. Former Texas representative Beto O'Rourke is doing little to dim speculation that he might jump into a field that has no clear front-runner.
Mr Castro is aware he lacks the name recognition of potential 2020 rivals or the buzz surrounding Mr O'Rourke, whose flirtations with 2020 have tantalised donors and activists after a close race last year against Senator Ted Cruz.
"Together we will show that hope can be bigger than fear, that light can be bigger than darkness, and that truth can be bigger than lies." #Julian2020— Julián Castro (@JulianCastro) January 12, 2019
But Mr Castro, who has repeatedly dismissed talk that an O'Rourke candidacy would complicate his own chances, has framed the neighbourhood and his upbringing as the story of an underdog.
Mr Castro was raised by a local Latina activist. After a brief career in law, he was elected mayor of the nation's seventh-largest city at 34.
It was not long before Democrats nationally embraced him as a star in the making, particularly one from Texas, where a booming Hispanic population is rapidly changing the state's demographics and improving the party's fortunes.
Mr Castro delivered the keynote speech at the 2012 Democratic National Convention. Two years later, Mr Obama picked him to lead the Department of Housing and Urban Development.
PA & Digital Desk