CHARLOTTE, N.C. -- Call them idealistic, but the Texas delegates in town for the Democratic National Convention are reading a lot into the selection of San Antonio Mayor Julián Castro to give Tuesday night's keynote address.Sure, it means a great deal for Castro's own political aspirations: The Democratic Party's rising star is already one of the nation's youngest mayors, a Stanford- and Harvard-educated 37-year-old Latino with an equally ambitious identical twin. Castro sat next to first lady Michelle Obama at the 2012 State of the Union address, another sign he was being primed for the national spotlight."They recognize Julián Castro is a potential statewide candidate -- very likely to be the first one we've had in a long time -- in the very near future," Texas Democratic Party Chairman Gilberto Hinojosa said.Most important for President Obama's re-election campaign, it's a play to Latino voters, who are crucial to sending him back to the White House for another four years. It's a population increasingly being courted by the GOP, which had its own youthful Hispanic -- U.S. Sen. Marco Rubio of Florida -- introduce Republican presidential nominee Mitt Romney on Thursday night in Tampa, Fla."I look at this much more as an effort to cultivate young Latino talent, much more about Julián Castro himself, than anything specific to Texas," said University of Texas political science professor and Texas Tribune pollster Jim Henson.But Texas Democrats hope there's another motivation. They want to believe that the Democratic National Committee -- which has long used the GOP-dominated state for fundraising junkets, fleets of Spanish-speaking volunteers and little else -- is beginning to consider Texas a state in play."It speaks to the president and the DNC's focus on Texas as a competitive state, either currently or in the near future," said state Rep. Rafael Anchía, D-Dallas."There's no question they want to highlight Texas," added Castro's brother, Democratic state Rep.Joaquin Castro, who is running for Congress in San Antonio, and who will introduce his twin on Tuesday night.Julián Castro, for his part, thinks he was selected for three reasons: because he's young, because he's Latino and because "San Antonio has done so well" under his leadership. Whether the DNC is sending a message to Texas, he said, is anyone's guess. "I hope so, but you'll have to ask them," he said.What the national spotlight means for Castro's own ambition isn't front and center right now. The mayor said he's going to run for re-election in San Antonio, so he won't have to make any decisions about a potential run for statewide office until 2017."As that tenure comes to a close, I'll look at what's out there -- but I'm not a fool about the numbers," he said. "There are 29 statewide offices, and Democrats are currently 0 for 29. Texas has to change before anyone can progress into those offices."The most optimistic members of the Texas delegation see the selection of Castro as a promise of future investment, a sign the national party no longer sees its chances of turning Texas blue as far-off."He's one of the most attractive leaders we've ever had in the Hispanic community," said Ben Barnes, a former Texas House speaker, former state lieutenant governor and a major Democratic fundraiser. "The Castro brothers are a great opportunity for us to showcase the future of Texas. It can have an impact, it can hasten the day."Latinos, who vote heavily Democratic, make up 38 percent of the Texas population. Some estimates show they could have a majority within eight years, presenting a huge opportunity for Democratic candidates, if they can harness it."The cliché is that demographics are destiny. But it also takes resources and organization, things the Democrats right now don't seem to have in any quantity in Texas," Henson said.