Julián Castro, the former housing secretary whose progressive presidential candidacy did not make significant inroads with Democratic voters but earned plaudits from the party’s left wing, has endorsed Senator Elizabeth Warren of Massachusetts, offering a possible lift for her candidacy less than one month before the Iowa caucuses.
Mr. Castro announced his endorsement on Monday morning, just days after he ended his own bid for the White House. In a statement, Mr. Castro cast Ms. Warren as the logical extension of his campaign’s social-justice-driven message, which seeks to correct inequities through targeted policy proposals. He will campaign with Ms. Warren this week, joining her Tuesday night at a rally at Kings Theatre in Brooklyn.
“There’s one candidate I see who is unafraid to fight like hell to make sure that America’s promise will be there for everyone,” Mr. Castro said in a video announcement released on Twitter. Ms. Warren, he said, “will make sure that no matter where you live in America — or where your family came from in the world, you have a path to opportunity, too.”
The endorsement is not a shock to close observers of the Democratic primary race — Mr. Castro and Ms. Warren made no secret of their shared affection for each other — but it formalizes a partnership that could help Ms. Warren reignite excitement at a critical moment.
Ms. Warren has fallen from her polling peak in early October, when she was hailed as the race’s ascendant front-runner and the standard-bearer for the party’s progressive wing. National polls now show Ms. Warren firmly in third, behind former Vice President Joseph R. Biden Jr. and Senator Bernie Sanders of Vermont, who has been aided by grass-roots progressive groups and by some high-profile endorsements of his own, including from popular House members like Representatives Alexandria Ocasio-Cortez of New York and Ilhan Omar of Minnesota.
It is unclear whether Mr. Castro’s name carries similar political weight. His presidential candidacy struggled to break through in a significant way, but he led the field on a number of progressive issues, including reparations, border decriminalization and housing inequality. He impressed liberal activist groups like the Working Families Party and the Center for Popular Democracy, even though they formally backed Ms. Warren and Mr. Sanders.
Ms. Warren thanked Mr. Castro for his support on Monday, calling him “a powerful voice for bold, progressive change.”
During the waning months of his campaign, Mr. Castro was a vocal critic of the primary calendar, pointing to how voters in Iowa and New Hampshire, who hold their nominating contests first, are overwhelmingly white. Ms. Warren has, at times, sidestepped that issue, saying once in South Carolina that she was just “a player in the game on this one.”