"As district director, I saw the need to secure the border and get our veterans the benefits they've earned," Barber said. "And every day, I see a middle class that's disappearing."

Barber also promotes his work for people with disabilities and the small business he operated with his wife.

And, in true Giffords fashion, he forged a centrist path on fiscal issues, warning of the risks of a government that grows too big.

"Running a family business, I saw how we can create jobs, and how government can get in the way," he says.

After stepping down from Congress, Giffords personally asked Barber to run to replace her, and she and her husband, Mark Kelly, have endorsed his campaign. Barber has said he also plans to run in a regular election in the fall for the full term starting in 2013.

Watch the ad: