One Year After Shooting, Giffords Leaves Congress -- PICTURES

Former Rep. Gabrielle Giffords, right, reacts after reciting the Pledge of Allegiance with Democratic National Committee Chairwoman Rep. Debbie Wasserman Schultz of Florida at the Democratic National Convention in Charlotte, N.C., on Thursday, Sept. 6, 2012.    (AP Photo/Charles Dharapak)

Former Rep. Gabrielle Giffords recites the Pledge of Allegiance with Democratic National Committee Chairwoman Rep. Debbie Wasserman Schultz of Florida at the Democratic National Convention in Charlotte, N.C., on Thursday, Sept. 6, 2012.   (AP Photo/Carolyn Kaster)

Former Rep. Gabrielle Giffords, right, blows a kiss after reciting the Pledge of Allegiance with Democratic National Committee Chairwoman Rep. Debbie Wasserman Schultz of Florida at the Democratic National Convention in Charlotte, N.C., on Thursday, Sept. 6, 2012.    (AP Photo/Charles Dharapak)

In an election to fill former Rep. Gabrielle Giffords, D-Ariz., congressional seat, Democratic candidate Ron Barber, right, celebrates a victory with Giffords, left, as he gives her a hug prior to speaking to supporters at a post election event, Tuesday, June 12, 2012, in Tucson, Ariz. (AP Photo/Ross D. Franklin, pool)

In an election to fill former Rep. Gabrielle Giffords, left, D-Ariz., congressional seat, Democratic candidate Ron Barber, right, celebrates a victory with Giffords and supporters at a post election event, Tuesday, June 12, 2012, in Tucson, Ariz. (AP Photo/Ross D. Franklin, pool)

This video image provided by House Television shows Rep. Gabrielle Giffords, D-Ariz. and House Speaker John Boehner of Ohio, on the floor of the House on Capitol Hill in Washington, Wednesday, Jan. 25, 2012. Giffords resigned from the House on Wednesday amid tears, tributes and standing ovations. (AP Photo/House Television)

This video image provided by House Television shows Rep. Gabrielle Giffords, D-Ariz. on the floor of the House on Capitol Hill in Washington, Wednesday, Jan. 25, 2012. Giffords resigned from the House on Wednesday amid tears, tributes and standing ovations, more than a year after she was gravely wounded by a would-be assassin. (AP Photo/House Television)

President Barack Obama greets retiring Rep. Gabrielle Giffords, D-Ariz., on Capitol Hill in Washington, Tuesday, Jan. 24, 2012, before delivering his State of the Union address. (PABLO MARTINEZ MONSIVAIS/AP)

Vice President Joe Biden greets retiring Rep. Gabrielle Giffords, D-Ariz. on Capitol Hill in Washington, Tuesday, Jan. 24, 2012, before President Barack Obama's State of the Union address. (PABLO MARTINEZ MONSIVAIS/AP)

Mark Kelly leans on the shoulder of his wife, Rep. Gabrielle Giffords, D-Ariz., at a memorial vigil on Sunday, Jan. 6, 2012, remembering the victims and survivors of the shooting one year ago in Tucson, Ariz.  (AP Photo/Ross D. Franklin)

Former astronaut Mark Kelly appeared on The Daily Show on Nov. 15 to promote his joint memoir with his wife, Rep. Gabrielle Giffords, D-Ariz., who was shot in the head during a constituent event in January.

In this undated photo provided by ABC, Giffords and Kelly are interviewed by Diane Sawyer on ABC's 20/20. (AP Photo/ABC, Ida Mae Astute)

This file image provided by Scribner shows the cover of the joint memoir of Giffords and her husband, Mark Kelly, titled Gabby: A Story of Courage and Hope. The book, written with Jeffrey Zaslow, was released on Nov. 15. (AP Photo/Scribner, File)

Giffords (right) was on hand at the White House for an Oct. 6 military retirement ceremony for her husband. (REP. GABRIELLE GIFFORDS/FACEBOOK)

Vice President Joe Biden presided over the ceremony honoring Kelly in the Secretary of War Suite in the Eisenhower Executive Office Building. (REP. GABRIELLE GIFFORDS/FACEBOOK)

Kelly and Giffords, who married in 2007, embrace after Kelly receives the Legion of Merit from Vice President Joe Biden. (REP. GABRIELLE GIFFORDS/FACEBOOK)

Giffords waves after arriving on the House floor on Aug. 1 for the debt-ceiling deal vote--her first time back since being shot in January. (AP)

Giffords prepares to leave the U.S. Capitol after the debt-limit vote. (AP Photo/Jacquelyn Martin)

Giffords and Kelly drive off after the Aug. 1 vote on Capitol Hill. (AP Photo/Susan Walsh)

This, one of the first two pictures showing Giffords's face after the shooting was posted to her Facebook page on June 12, 2011. (Photo from Facebook)

In this photo taken from Facebook, Giffords is shown with an unidentified woman. This is one of two photos posted to Giffords's page on June 12. (Photo from Facebook)

Photos of Kelly holding Giffords's hand in her hospital room were among the first released after her shooting. (Courtesy Photo)

A close-up photo of Giffords and Kelly holding hands in the hospital. (Courtesy Photo)

On Jan. 5, House Speaker John Boehner reenacts Giffords's swearing-in for the cameras. (AP Photo/Susan Walsh, File)

Giffords speaks to a man identified as Dr. Gary Thrasher in a 2010 photo provided by her congressional reelection campaign. (REUTERS/Giffords for Congress/Handout)

Giffords and Kelly, shown here in an undated photo, decided to write a joint memoir after her shooting. (AP Photo/Office of Rep. Gabrielle Giffords, File)

Giffords (right) and chief aide Pia Carusone attend an event in summer 2009. (Photo courtesy of the Rep. Giffords office)

On the stump in 2006, then-candidate Giffords greets Paul Glinco in the parking lot of Faith Tabernacle Church in Tucson, Ariz. (AP Photo/John Miller)

Democrat Giffords holds forth during a preelection debate at Pima Community College in Tucson on Oct. 17, 2006. (AP Photo/John Miller)