Giffords's saguaro-studded district has large military and senior populations that often turn to her office for help navigating their federal benefits. The district also shares a border with Mexico and famously struggles with problems related to illegal immigration and the drug trade. Some worry that Giffords's absence removes an important voice in Washington.
"There's so much going on in Tucson that we need representation. People who are not from border states don't understand," Lee Silva, 40, a Tucson resident who voted for Giffords said recently as she stood near a sprawling collection of cards, candles and stuffed animals outside the hospital where Giffords and other victims of the Jan. 8 rampage were taken. "It's not just illegal immigration, but drugs. They do a lot of damage to the communities they touch."
Colleagues and friends say Giffords's work will go on in her absence. Her staff reopened her Tucson congressional office one day after a gunman opened fire at a constituent event, killing six and injuring 13, including Giffords. They say her priorities are well known and that her staff and friends in Congress can carry out what they know to be her wishes.
In Washington, Giffords is known as a supporter of solar energy and veterans issues, but her primary focus in recent years has been border security. Last year, she helped secure $600 million in federal money to beef up U.S. Border Patrol ranks and buy new monitoring technology. Members of Congress on both sides of the aisle have offered to carry legislation for her on border security and other issues if it comes to that, said Pia Carusone, Giffords's chief of staff.
"There are all these people from both parties that we've been working with over the last four years that we can turn to if needed," Carusone said.
More pressing, Carusone said, will be the demands back home, where she is known for her attentive constituent services. Requests for help have continued to come in since the attack. Staff members for Rep. Raul M. Grijalva (D), who represents a neighboring district, have pitched in, as have many former interns who showed up at the office offering to help.
Ron Barber, her district director, said the staff has been determined to keep up their work despite the blow they sustained. Barber and another staff member were wounded in the shooting. A third, Gabe Zimmerman, was killed.
On Friday, Barber attended the funeral of a slain border agent even though he had been ordered by a doctor to stay home after sustaining two gunshot wounds. He felt compelled to attend, he said, because Giffords would have been there.
"Her voice will not be diminished," Barber said, speaking for the staff. "We're not as articulate as she is, and of course she is a voting member of Congress, but we know what she wants. We know what her vision is, and we are ready to execute it."
Only a handful of times in recent history have health problems prevented members of Congress from performing their duties. Sen. Tim Johnson (D-S.C.) was out for several months in 2006 and 2007 because of a brain hemorrhage. Rep. Gladys Noon Spellman (D-Md.) suffered an incapacitating heart attack during a campaign event in 1980, leading House Democratic leaders to declare her seat empty.
A seat held by a disabled member becomes vacant only if the member retires or at the end of the lawmaker's term.
Giffords's condition is improving daily, according to a statement from Memorial Hermann-Texas Medical Center, where she is being treated. But doctors are giving no updates on the buildup of brain fluid that has kept her in intensive care, according to the Associated Press.
A hospital statement released Sunday afternoon said Giffords will continue to receive therapy in the intensive care unit "until her physicians determine she is ready for transfer" to a nearby center where she would begin a full rehabilitation program.
Doctors warn that patients in her condition sometimes plateau, and they have declined to describe a best-case scenario.
Giffords's husband, astronaut Mark Kelly - cognizant of the significance of removing the congresswoman from the district she represents - has taken pains to explain his rationale behind moving her to the Houston rehabilitation center, which has a top-notch reputation and is near his home. He said so in a statement, a speech and a tweet last week that ended, "back in Tucson ASAP!"
Kelly, who has emerged as an eloquent spokesman for his wife, has kept himself abreast not only of issues connected with her medical treatment but also on matters relating to her congressional duties, Carusone said.
For residents of this swing district, Giffords's shooting has become a galvanizing force that has connected them over the broad suburban avenues and political divides that separate them. They have communed over the makeshift memorials that have been growing outside her office, at the Safeway near the shooting, and at the hospital.
The memorials will remain until next week, when they will begin to be dismantled. Plans are underway to erect a permanent remembrance at the hospital.
"We've been praying for her, and we actually think she will be back," retired contractor Miguel Escalante, 77, said as he gazed down at the display outside the trauma center. "She will be back to work again in no time."