They are on opposite ends of the political spectrum with regard to policy, but San Antonio Mayor Julian Castro and Texas Senate candidate Ted Cruz have several things in common. Both Castro and Cruz are of Hispanic descent - Castro is Mexican-American, Cruz is the son of a Cuban-American father and an American mother.

Both men are graduates of Harvard Law school and, most importantly, are considered rising stars within their respective parties, as July 31, Election Day, marks a significant date in their careers.

Cruz, the state's first Hispanic solicitor general, is a Tea Party favorite whose Senate campaign has garnered attention from across the country.

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Cruz, 41, faces the biggest test of his career yet, a runoff today with Lt. Gov. David Dewhurst for the Republican Party nomination for Senate. Texas is a Republican stronghold, so today's contest, which Cruz is favored to win, according to recent polling, will likely decide whether Cruz becomes the next senator from the Lone Star state.

For Castro, 37, today marks the day his name got elevated to the national stage. The San Antonio mayor, who has been viewed as a rising Democratic star for several years now, will be the keynote speaker at this summer's Democratic National Convention in Charlotte, N.C.

It's a platform that has launched many a Democratic leader, including Barack Obama, who was a state senator and candidate for Senate in Illinois in 2004 when he was tapped to keynote at the DNC in Boston.