Among the dead were federal Judge John Roll and 9-year-old Christina-Taylor Green, the granddaughter of former major league manager and general manager Dallas Green and the daughter of Dodgers scout John Green.
Giffords, severely wounded, has apparently won the battle for her life though the eventual extent of her recovery remains up in the air.
But there has been considerable disagreement on what led the gunman, sane or insane, to pick the congresswoman as his primary target.
The Pima County, Ariz., sheriff points to what he called the poisonous political atmosphere surrounding Giffords. Others, such as radio's Rush Limbaugh and former Alaska Gov. Sarah Palin -- who have been cited by some critics as two major contributors to that atmosphere -- scoff at that theory, and say liberals are just trying to smother voices from the right by linking politics to the massacre.
The debate over liability can be divided into two parts.
One, is there anyone morally responsible for leading the gunman to target Giffords and the others? Two, can any third party be held responsible in court, at least civil court, for the same thing?
The first part of the debate will be decided by public opinion. The second part may be answered by the U.S. Supreme Court later this term.
The New York Times paints a vivid picture of the political atmosphere surrounding Giffords, a Democrat, including death threats.
She ran for re-election against Jesse Kelly, a Tea Party-backed Republican, who attacked Giffords on healthcare and immigration. Kelly held a "targeting victory" fundraiser in which he invited contributors to shoot an M-16 with him.
Kelly's campaign rhetoric was hard-edged, the newspaper reported.
"These people who think they are better than us, they look down on us every single day and tell us what kind of healthcare to buy," he said. "And if you dare to stand up to the government they call us a mob. We're about to show them what a mob looks like."
Kelly also appeared in a Web ad holding an assault rifle.
Giffords won the race but it was close.
Hours after she voted for the Obama administration's healthcare package last March, the door of her district office in Tucson was smashed. Giffords, like other Democrats, also had been verbally battered at town hall meetings on healthcare.
The Times said the door-smashing incident concerned Giffords and her staff, who began letting police know where she would be making public appearances.
"She was extremely concerned about it," Thomas Warne, a friend and fundraiser, told the Times. "She was concerned about various threats that the office had received: They were general threats on the office itself, on her life."
U.S. Rep. Raul Grijalva, a Democrat from the neighboring 7th District, told the Times he was nonplussed by the level of animosity in Gifford's 8th District.
"We commiserated about the tone of the campaign and talked about how ugly it was and how angry people were," he told the newspaper. "Philosophically, she is more moderate and more centrist than me, and I couldn't understand that level of ire and that level of hatred against someone who is trying to accommodate and find common ground."
But Randy Graf, a Republican who lost to Giffords in the 2006 race, said he did not believe the political anger had any role in what happened.
"People are trying to rationalize an irrational event and in the process of doing that they're blaming the blameless," he told the Times. "The blame is being aimed at everything from the past campaign to the Tea Party when it should rest, by all reports, on the shooter himself."
Jared Lee Loughner, 22, of Tucson was arrested for the shootings. Officials say so far he appears to have acted alone.
The past actions of Tea Party darling Palin have drawn even more attention from critics and the media. In the November elections, Palin had marked congressional 20 districts with cross-hairs -- where she thought Democratic incumbents should receive particular attention for defeat. Among the districts was Giffords'.
Palin's Mama Grizzly persona -- she frequently tells political supporters "don't retreat, reload" -- also provided fodder for critics who say she contributes to a violent atmosphere.
But the former Republican vice presidential candidate came out with a video on her Web site last Wednesday portraying herself as the victim. The video had an uncharacteristic tone of self-pity, indicating Palin was hurt by the criticism.
The former Alaska governor said she had listened "with concern and now with sadness to the irresponsible statements from people attempting to apportion blame for this terrible event. ...
"Acts of monstrous criminality stand on their own. They begin and end with the criminals who commit them, not collectively with all the citizens of the state, not with those who listen to talk radio, not with maps of swing districts used by both sides of the aisle, not with law-abiding citizens who respectably exercise their First Amendment rights at campaign rallies, not with those who proudly voted in the last election."
She cited the "journalists and pundits" as the real culprits.
"Especially within hours of a tragedy unfolding," she said, "journalists and pundits should not manufacture a blood libel that serves only to incite the very hatred and violence that they purport to condemn. That is reprehensible. There are those who claim political rhetoric is to blame for the despicable act of this deranged, apparently apolitical criminal."
In the days after the shootings, Pima County Sheriff Clarence Dupnik told ABC News Limbaugh's rhetoric against elected officials is "irresponsible."
"The kind of rhetoric that flows from Rush Limbaugh, in my judgment he is irresponsible, uses partial information, sometimes wrong information," Dupnik said. Limbaugh "attacks people, angers them against government, angers them against elected officials and that kind of behavior in my opinion is not without consequences."
Dupnik told ABC: "The vitriol affects the (unstable) personality that we are talking about. You can say, 'Oh, no it doesn't,' but my opinion is that it does."
Politico reported Limbaugh also put his considerable weight into the fray, saying the left was trying to use the shooting "for their political benefit," and alleging Democrats were waiting for a reason to regulate their political opponents.
"I wouldn't be surprised if somebody in the Obama administration or some (Federal Communications Commission) bureaucrat or some Democrat congressman has it already written up such legislation, sitting in a desk drawer somewhere just waiting for the right event for a clampdown," Limbaugh said. "They have been trying this ever since the Oklahoma City bombing."
So far, Limbaugh and Palin appear to be winning the public opinion battle over moral responsibility for the shootings.
A CBS News poll indicated 57 percent of the U.S. public said the shootings were not related to political rhetoric while 32 percent said they were. A poll conducted by Vision Critical, formerly Angus Reid Strategies, indicated 51 percent said the shootings should be regarded as an isolated incident while 31 percent linked the shootings to a poisonous political atmosphere.
As to the second part of the debate -- whether anyone can be brought into court -- that may be decided by the Supreme Court in a decision that could broadly define the limits of free speech.
The justices are considering a ruling in the case of the Westboro Baptist Church of Topeka, Kan., whose members show up at the funerals of service members to aggressively protest what they consider the military's toleration of homosexuality and the toleration of homosexuality in the United States.
The father of a Marine killed in the line of duty in Iraq took the protesters to court in Maryland. A jury agreed with the Marine's family, holding the church members liable for disrupting the funeral. A federal judge upheld the verdict and $5 million in damages for emotional distress, but a federal appeals court reversed, saying the protesters were using "rhetorical hyperbole" absolutely protected by the First Amendment.
Normally, the federal courts and particularly the Supreme Court wouldn't touch a political case with a 10-foot pole.
But if church members lose their case at the Supreme Court, and the decision is broad enough, it could open the gates for civil suits against violent speech that incites crime -- except that is not likely to happen given the First Amendment and high court precedent on abortion protests in the 1990s. The most likely result is that the justices will defend court action that creates a limited buffer zone between the church protesters and funerals, but will find their speech protected by the First Amendment.
Meanwhile, in a move aimed at the Westboro protesters, Arizona has enacted a law making it illegal to picket "within 300 feet of any home, cemetery, funeral home or house of worship before, during or immediately after a ceremony or burial," the Arizona Daily Star reported.
Westboro church members had threatened to protest at the funerals of the Tucson victims but retracted the threat after being offered radio time.
In a telephone interview with the New Times in Phoenix, Shirley Phelps-Roper, a leader of the Westboro Baptist Church, said Loughner had acted on God's instructions.
"God sent the shooter -- that guy's bat-(expletive) crazy -- but God sent him."