San Antonio Mayor Julian Castro will be the keynote speaker at the Democratic National Convention in Charlotte, N.C., in September — a clear sign of the importance of the Hispanic vote to President Obama’s re-election math this November.

President Barack Obama's walks with from left, Texas State Rep. Joaquin Castro (D), his twin brother San Antonio Mayor Julian Castro and Congressman Charles Gonzalez, upon his arrival Tuesday, July 17, 2012 in San Antonio. (AP Photo/Bahram Mark Sobhani)

“Having both the First Lady and Mayor Castro speak on the opening night of our convention will bring together two incredible leaders whose life stories both embody the promise of America, that if you work hard and play by the rules, you can make it,” said Los Angeles Mayor Antonio Villaraigosa, the chairman of the convention.

Democrats’ selection of Castro suggests the party is going to be making a full-court press to turn out Latino voters in November. Western swing states with substantial Hispanic populations like Nevada and Colorado could be crucial for the president in the fall.

In 2008, Obama took 67 percent of the Hispanic vote to just 31 percent for Arizona Sen. John McCain.

Castro is something of a rising star in Democratic politics. He’s young, telegenic and comes from humble roots (he was raised by a single mother and, like Obama, went on to receive a degree from Harvard Law School).

Castro’s family is no stranger to politics. His twin brother, Joaquin Castro, is a state legislator running for Congress (and heavily favored to win) in Texas’s 20th District.