By Patricia Zengerle
WASHINGTON (Reuters) - The 2012 Democratic convention speaker schedule is focused on two things: the crucial Hispanic vote and a throwback to the 1990s when a Democratic president oversaw economic good times.
The party announced that San Antonio Mayor Julian Castro will deliver the keynote address on September 4, the first day of the three-day meeting in Charlotte.
A rising Democratic star seen as potentially reaching national office, Castro, 37, is the first Hispanic American to fill that convention slot.
"He shows a party that is open, diverse and speaking to younger Americans in new and direct ways," said Neera Tanden, a former Obama aide who is now president of the left-leaning Center for American Progress.
"Successful conventions have showcased the next generation of leaders as well as the real stars of the party," she said.
As a city mayor, Castro also sends a message to voters that the Democrats are about more than just the capital city, in a year when Obama's Republican opponent, former Massachusetts Governor Mitt Romney, is running as a Washington outsider.
Castro follows in the footsteps of Obama, who made his first big splash on the national political stage as the keynote speaker at the Democratic convention just four years before winning the White House.
Former President Bill Clinton will also play a big role by delivering the speech formally nominating Obama for re-election on the Wednesday night of the gathering.
Clinton is a gifted speaker, rated by some as even better than Obama himself. But more importantly, the last Democrat in the White House presided over eight years of relative peace and prosperity from 1993 to 2001 compared with the economic tough times during Obama's administration.
Clinton, hugely popular 11 years after leaving office, is seen as more moderate than Obama. He will appeal to independent voters nostalgic for the boom years of the 1990s.
The former Arkansas governor is also more highly rated than Obama among white voters, especially men.
"The party.... wants to counteract some of the Republican attacks that this is an administration that is unfriendly to business and unfriendly to economic prosperity by having a former president who embodied both," said Princeton University's Julian Zelizer.
"They also want to send a signal that they are going to be tough in the fall. Bill Clinton is a tough partisan who doesn't back away from really going after the Republicans," he said.
WILL HISPANICS SWING THE ELECTION?
The Democrats are relying on strong support from Hispanics to deliver a second term for Obama. In particular, several states where the election is expected to be close -- including Florida, New Mexico, Colorado and Nevada -- are home to large numbers of Hispanic voters.
The choice of Castro will also help shore up Obama's Hispanic support if Romney selects Florida Senator Marco Rubio, who is Cuban American, as his vice presidential running mate.
Hispanics account for about 16 percent of the overall U.S. population, but less than half are adults eligible to vote. Obama won two-thirds of their votes in 2008 when he first took the White House. Polls show him with an even larger advantage among Latinos this time around.
Elizabeth Warren, a U.S. Senate candidate from Massachusetts who is especially popular with the party's left flank, delivers an address on Wednesday night, just before Clinton.
First Lady Michelle Obama will speak on the convention's opening night before Castro, the youngest mayor of a major U.S. city. San Antonio is the seventh largest U.S. city with 1.4 million people, about two-thirds of whom are Hispanic.
Vice President Joe Biden will deliver his acceptance speech on Thursday at Charlotte's 74,000-seat National Football League stadium, before Obama takes the podium.
The Republicans hold their convention in Tampa, Florida, a week before the Democrats. They have not yet released their convention speakers list.
The Republicans are struggling this year to balance party factions. Some want the convention to use the glare of national television exposure to show a relatively moderate face to appeal to independent voters.
But other factions like the Tea Party movement and social conservatives, who backed some of Romney's rivals like Michele Bachmann, Herman Cain and Rick Santorum in the nomination fight, want to send a more conservative message.
Some media reported that New Jersey Governor Chris Christie had been offered the Republican keynote speaker's spot. His office has not confirmed those reports.
The last two Republican presidents, President George Bush and President George W. Bush, will not attend the Republican convention. Dick Cheney, George W. Bush's vice president, is also skipping Tampa.
(Editing by Alistair Bell and Andrew Hay)