

Rep. Gabrielle Giffords' (D) of Arizona stands with House Speaker John Boehner (R) of Ohio during a farewell ceremony for Giffords on the floor of the House of Representatives, in this still image taken from video, January 25, 2012. Giffords, wounded a year ago in a deadly Tucson shooting spree, stepped down from the US Congress on Jan. 24 to focus on her recovery. HouseTV/Reuters
This video image shows Rep. Gabrielle Giffords accompanied by Democratic National Committee Chair Rep. Debbie Wasserman Schultz (D) of Florida on the floor of the House on Capitol Hill in Washington, Jan. 25, 2012. House Television/AP
President Obama hugs retiring Rep. Gabrielle Giffords on Capitol Hill in Washington prior to giving his 2012 State of the Union address.
Rep. Gabrielle Giffords (D) of Arizona announces that she will resign from Congress in this still image taken from a video posted on her Facebook page on Sunday. Giffords, shot in the head in a shooting spree in Tucson a year ago, said she will step down this week from the US Congress to focus on her recovery. Gabrielle Giffords Congressional Office/Reuters
Arizona Congresswoman Gabrielle Giffords recites the Pledge of Allegiance during a memorial service at the University of Arizona campus in Tucson on January 8. Laura Segall/Reuters
Mark Kelly leans on the shoulder of his wife, Rep. Giffords, at a memorial vigil remembering the victims and survivors of the shooting that wounded Giffords, 12 others and killed six about one year ago in Tucson, Ariz. Ross D. Franklin/AP
People hold candles during a memorial vigil remembering the victims and survivors about one year after a gunman shot Congresswoman Giffords and killed six others in Tucson, Ariz. Ross D. Franklin/AP
Rep. Giffords smiles during a memorial service at the University of Arizona campus in Tucson on January 8. Laura Segall/Reuters
Rep. Giffords is embraced by Pam Simon, one of those wounded, during a memorial vigil Jan. 8 in Tucson, Ariz. Ross D. Franklin/AP
Rep. Gabrielle Giffords (D-AZ) arrives at the Capitol in Washington with her husband Mark Kelly (r.) and Rep. Debbie Wasserman Schultz (D-FL) to vote on the debt limit bill in the House. Giffords has been recovering from a gunshot wound to the head sustained Jan. 8, 2011, in Tucson, Ariz. Tom Williams/Roll Call/Newscom
Rep. Gabrielle Giffords sits with her mother Gloria Giffords at the TIRR Memorial Hermann Hospital in Houston on May 17, 2011. Ms. Giffords was shot in Tucson, Ariz., at a public appearance, where she met with constituents on Jan. 8. Six people were killed in the shooting, and Giffords was among 13 people who were wounded. P.K. Weis/southwestphotobank.com/AP/File
This photo of Rep. Gabrielle Giffords on the road to recovery was posted to her public Facebook page by her aides on June 12, 2011. Ms. Giffords took office in Jan. 2007, emphasizing issues such as immigration reform, embryonic stem-cell research, alternative energy sources, and a higher minimum wage. P.K. Weis/AP Photo/File
From left, Ellie Steve, Lucia Reeves, and Zoe Reeves gather for a candlelight vigil outside the offices Rep. Gabrielle Giffords in Tucson, Ariz., on Jan. 9, 2011. Chris Carlson/AP/File
Rep. Gabrielle Giffords takes part in a reenactment of her swearing-in on Capitol Hill in Washington on Jan. 5, 2011. Susan Walsh/AP/File
Rep. Gabrielle Giffords meets with constituents in Douglas, Ariz.. in an undated 2010 photo provided by her congressional campaign. Giffords for Congress/Handout/Reuters/File
Rep. Gabrielle Giffords leaves the National Guard base in Tucson, Ariz., with Brigadier General Michael G. Colangelo (l.) for the 60-mile ride to the border town of Nogales, where she made a tour of the troops patrolling the US-Mexico border on Sept. 10, 2010. Gary M. Williams/EPA/Newscom/File
Rep. Gabrielle Giffords waves to the crowd on election night with her husband, astronaut Mark Kelly, at the University Marriott near the University of Arizona on Nov. 4, 2008. David Sanders/Arizona Daily Star/Rapport Press/Newscom//File
Rep. Gabrielle Giffords gives a tour of Statuary Hall in the Capitol in Washington to Shuttle Discovery STS-124 astronauts Mission Specialist Akihiko Hoshide, of Japan, and her husband, Commander Mark Kelly, on July 17, 2008. Bill Clark/Roll Call Photos/Newscom/File
Rep. Gabrielle Giffords testifies before the House Budget Committee in Washington in 2008. Prior to serving in Congress, Ms. Giffords was both an Arizona state representative and senator. Douglas Graham/Roll Call Photos/Newscom/File
Representatives-elect including Dean Heller (R-NV) (top r.) and Gabrielle Giffords, to his left, prepare for the freshman class picture for the 110th Congress on the House steps in Washington. Tom Williams/Roll Call Photos/Newscom/File