Castro has been seen as a rising star in the Democratic party because he has the economic chops to match his populist appeal. (Courtesy Creative Commons/ Dawn Megli)

Julian Castro, the San Antonio mayor and rising star in the Democratic party, illustrated that diversity as the first Latino to deliver a keynote address at the convention. Young, successful, and a third generation Hispanic immigrant, Castro appeals to key voting blocks.

The Obama campaign didn't waste any time hyping the Texas politician and Stanford grad whose young career has drawn comparisons to the meteoric rise of Barack Obama after his speech at the 2004 DNC.

The Obama campaign released a video hours before Castro's keynote address highlighting his family's pull-yourself-up-by-the-bootstraps story. The video frames Castro's life as "really an American dream story" which hits upon his grandmother's immigration to the United States and her years as a domestic worker so that Castro's mother could have a chance to attend college. 

Economics are as important as demographics, however, and Castro's keynote speech reclaimed the theme of economic opportunity from the GOP. While the rhetoric at the RNC focused on individual success, Castro stressed the role of government policy in creating a culture of success.

"My family's story isn't special. What's special is the America that makes our story possible," Castro said in remarks released in advance of his speech. 

The remarks were an oblique reference to last Tuesday's slogan of "We Built It" at the RNC. The GOP seized on an Obama comment that "you didn't build it," a reference he made to the role infrastructure plays in helping small businesses, and used it to paint him as antithetical to individual success. Castro's speech poked holes in the talking point which became the dominant refrain of the GOP in Tampa.

Castro took aim at the fiscally tight-fisted Tea party contigent, as well, by pitting the popular Pell grant program agaisnt further cuts to education.

"We all understand that freedom isn't free. What Romney and Ryan don't understand is that neither is opportunity," Castro said. "We have to invest in it."

In a play for the liberal vote which has become increasingly disenchanted with Obama, Castro borrowed a line from the Occupy movement to resurrect a populist complaint over tax rates which favor the wealthy.

"It's a choice between a country where the middle class pays more, so that millionaires can pay less," Castro said. "Or a country where everybody pays their fair share."

Republican presidential candidate Mitt Romney has come under fire since he admitted, with a net worth has been estimated around $250 million, he pays a tax rate near 13 percent. The average federal tax rate for 2009, the most recent year for which data is available, was just under 18 percent. 

While Castro is stumping for Obama Tuesday, Castro's rising profile in the Democratic party has many looking at the prospects for the next convention. Mark McKinnon, former George W. Bush adviser, said Castro "has a very good chance of becoming the first Hispanic president of the United States."

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Reach Staff Columnist Dawn Megli here; follow her on Twitter here.