San Antonio Mayor Julian Castro gives the keynote address at the Texas Democratic Convention in Houston on June 8. (Pat Sullivan/AP)

Eight summers ago, a fresh faced politician took to the podium for a keynote address at the Democratic convention that launched him onto the national stage and a path to the White House.

Among the viewers of then Sen. Barack Obama's national debut was Julian Castro, now mayor of San Antonio, who will follow in Obama’s footsteps as keynote speaker at the Democratic convention this year in Charlotte.

In picking Castro, Democrats are acknowledging the power of the Latino vote in the 2012 race for the White House and the changing demographics across the country. In attempting to fill Obama’s shoes, Castro, 37, is set to raise his national profile and lay the foundation for possible statewide or national ambitions.

“He could be the first Latino President or Vice President and it would be reasonable to suggest that Julian would be well positioned to be the Democratic nominee for Texas Governor, ” said Walter Clark Wilson a professor at the University of Texas at San Antonio. “Right now he is doing everything right to set up these kinds of situations for the future.”

While still relatively unknown outside of Texas, Castro is considered a rising star among Democrats and has cultivated a relationship with Latino leaders across the country.

In December 2009, he sat a few chairs down from Obama at a roundtable discussion at the White House on jobs and green energy that was captured on video.

Obama had a joke at the young mayor’s expense.

“I thought he was on our staff. I thought he was an intern.” Obama said, as Castro noted that he was the youngest person at the table. “This guy’s a mayor? I’m messing with you. I know who you are.”

Like Obama, Castro rose from a humble background, was raised by a single mother and went on to get an elite education--he has degrees from Stanford University and Harvard Law School.

Castro, who hosted Obama last month in San Antonio, is among the vanguard of younger minority politicians who have roots in traditional ethnic politics but have also been able to move into the political mainstream.

The son of Rosie Castro, a prominent leader of the Mexican-American Civil Rights movement in Texas, Castro is one half of a political duo that includes his twin brother Joaquin, a member of the Texas state legislature who is running for a Congressional seat.

“He has taken the traditional Latino Civil Rights agenda and rather than cast it aside, he’s had a modern interpretation of the Latino world view,” said Antonio Gonzalez, a political activist who is president of the William C. Veasquez Institute. “He isn’t post-racial. He gets the inclusion narrative of an immigrant community and he doesn’t cast race aside. But he broadens the issues to include environment and the economy and the growth of business.”

Castro will be the first Latino to keynote the DNC’s convention--in 1984 Katherine Davalos Ortega, then the U.S. Treasurer, keynoted the Republican convention.

For Democrats, maintaining Obama’s edge among Latinos will be key to victory in November--in 2008 he won 67 percent of the Hispanic vote and a July Gallup poll shows him leading Romney among registered Latino voters 60 to 28 percent.

Yet the choice of Castro highlights a thin Democratic bench to some.

“Democrats had to dig deep and go to a local official to find a fresh Hispanic face on the stage,” said Ana Navarro, Sen. John McCain’s National Hispanic Co-Chair in 2008. “We have three Republican statewide Hispanics that have been elected since the last Convention, with the added bonus all three represent swing states, all three have compelling personal stories and I fully expect to see at least one if not all three showcased in Tampa.”

The Republican convention will be held in Tampa in late August, a week before the Democrats meet in Charlotte.

In a video released Tuesday by the Democratic National Committee, Castro recalled his mother’s activism, and highlighted Obama’s record on health care, the economy and foreign policy.

“He will be a good surrogate on the road, not that you need to do that much because the president is running well with the Latino vote, the question is enthusiasm,” Gonzalez said. “It’s tough on the grassroots, people were giddy in 2008, but you don’t have that anymore. There is a feeling of being beaten down by life, particularly with young people. Maybe Julian can drum up the troops. He will add a lot of value and energy. If I was them I would wind him up and let him go.”