Hillary Clinton Passes Over Julián Castro for VP

^{Editor's note: This story has been updated with additional comment.}

Former U.S. Secretary of State Hillary Clinton has named U.S. Sen. Tim Kaine of Virginia as her vice presidential running mate, a move that will disappoint scores of Texas Democrats who hoped she would select a son of San Antonio, U.S. Secretary of Housing and Urban Development Julián Castro.

Castro registered his approval of Clinton's choice minutes after she announced it.

"#Clinton/Kaine! A winning ticket for America," Castro wrote on Twitter. "#ImWithThem." 

Despite years of build-up as a vice-presidential contender, few in national politics viewed Castro as likely to be Clinton's pick. In recent months, his name faded from nearly all conversations as Kaine, U.S. Labor Secretary Thomas Perez and U.S. Sen. Elizabeth Warren of Massachusetts rose to the top of the betting pools. 

At 41, Castro is a telegenic presence and even met with Clinton last week, according to The Associated Press.

But he lacked experience with Congress and in foreign policy, two skills viewed by many as necessary for anyone being considered to be within a heartbeat of the presidency. 

Moreover, other Democrats complained that his Spanish skills paled in comparison to those of other contenders. There were also knocks on his lacking the relationships and Congressional fluency that Vice President Joe Biden brought to the Democratic ticket in 2008, and concerns that his time as San Antonio Mayor was insufficiently groundbreaking.

• Read More Is Julián Castro Experienced Enough To Be VP?

Former U.S. Rep. Pete Gallego of Alpine said Clinton and Kaine will make a "strong, effective team" — but made clear his original preference for Castro.

"As a proud Texan, I was very much rooting for Julián Castro to be on this year's historic ticket," read a statement from Gallego, who is running to reclaim his seat in Texas' only competitive Congressional race in November. "Secretary Clinton had a tough choice to make, and making tough choices is something she does well."

Despite the widespread disappointment among Texas Democrats over Clinton's pick, there are few signs Castro set his political career back in navigating the dicey vice-presidential consideration process, and he could have another shot at higher office down the road.

He will face a crossroads in January, when Obama leaves office and his own term as HUD secretary wraps up.

Both he and his twin brother, U.S. Rep. Joaquín Castro, are often mentioned as possible contenders to challenge U.S. Sen. Ted Cruz in 2018.