Gabrielle Giffords, 40, has represented Arizona's 8th District since 2007 after serving in the Arizona legislature from 2001 to 2005. She took the seat of moderate Republican Rep. Jim Kolbe, who retired from the U.S.-Mexico border-area district in 2006.
While generally considered to be a swing district, John McCain easily carried Arizona's 8th in 2008 with 52 percent of the vote, and Republicans held the seat until Giffords was elected in 2006.
Giffords, a third-generation Arizonan, ran a Tucson tire business she inherited from her father before entering politics. She's the only former tire dealer in Congress.
An up-and-coming Blue Dog Democrat, Giffords was barely elected to a third term in her Republican-leaning district, aided by a magnetic personality and fractures within the state's Republican party. In 2010 Real Clear Politics listed her as one of the "Top Ten Rising Power Players in the U.S. Congress."
Giffords is known for a cheerful and energetic disposition. "I just read the First Amendment!" she said -- "gleefully," according to The New York Times -- after stepping off the House floor during the first-ever reading of the Constitution on Wednesday. "Reflecting on the Constitution in a bipartisan way is a good way to start the year."
Her husband, Cmdr. Mark E. Kelly, 46, is a NASA astronaut. Giffords married Kelly in 2007; they have two children. House Democratic Leader Nancy Pelosi told HuffPost she liked to talk to Kelly about the cosmos.
Giffords serves on committees for armed services, foreign affairs, and science and technology. She's the chairwoman of the Subcommittee on Space and Aeronautics.
"Gabby is a friend," Rep. Brad Miller (D-N.C.) told HuffPost. "We serve on the Science and Technology Committee together, and both chaired subcommittees. She is a conscientious member of the committee and of Congress, and her company is a pleasure."
First elected in 2006 in a mid-term that gave Democrats control of the House of Representatives, Giffords has voted with Democrats on health care reform, Wall Street reform, and the 2009 stimulus bill. But she has also showed an independent streak, opposing, for instance, the auto bailout and cash-for-clunkers legislation.
Giffords is a strong supporter of gun-ownership rights under the Second Amendment. In 2008, when Arizona Democrats were divided over the landmark DC gun ban case District of Columbia v. Heller, Giffords, who reportedly owned a Glock handgun at the time, called gun ownership a constitutional right and an "Arizona tradition," according to spokesman C.J. Karamargin.
Giffords has been the target of political threats before. In the wake of the health care vote, health care overhaul foes threw a brick through the front door of her Tucson district office, shattering the glass. A protester at a summer 2009 event -- similar to the meet-and-greet where she was shot Saturday -- accidentally dropped a gun on the floor. "We have never felt the need before to notify law enforcement when we hold these events," her spokesman said.
When asked if she had any enemies, Giffords' father reportedly wept. "'Yeah,'" he told The New York Post. "'The whole Tea Party.'"
Giffords has also been active on immigration issues, backing increased border security measures as well as creating a path to legalization for undocumented workers. (Democratic Rep. Raul Grijalva, who represents an adjacent district and has also been outspoken on immigration issues, closed his district office this summer when someone shot a bullet through his office window.)