The senseless shooting in Tucson, Arizona that left six dead and 13 wounded - including the congresswoman Gabrielle Giffords - traumatised the United States, threatening for a moment to exacerbate an already deep political divide. Shocked reactions in the aftermath of the event have been quite revealing.
The initial response of many Americans was simply to fall silent and to mourn the loss of life. The silence, however, was soon shattered by the partisan discord that permeates American political life, affecting everything from domestic legislation to foreign policy.
The incident recalled past dramatic events that also evoked powerful public responses: the assassinations of John and Robert Kennedy and Martin Luther King; the trauma after September 11; even the sense of hope generated by the signing ceremony between Yasser Arafat and Yitzhak Rabin on the White House lawn. In each case, the sense of resolve and introspection eventually faded, but there was a kernel of truth that remained.
For now, what is most apparent is the acrimony. Liberal commentators have accused some right-wing groups of creating a charged political atmosphere that fomented this kind of violence. They point to examples of violent imagery targeting liberal politicians. Singled out for special criticism was the former Republican vice presidential candidate Sarah Palin, who has a fondness for gun imagery. She once famously told her supporters not to "retreat, but reload" and her website featured a map of Democratic candidates (including Ms Giffords) targeted for defeat with their districts in the cross-hairs of a gun sight.
One TV commentator, Keith Olbermann on MSNBC, was especially pointed in his criticism: "If Sarah Palin ... does not repudiate her own part, however tangential, in amplifying violence and violent imagery in American politics, she must be dismissed from politics."
Mrs Palin and others on the right were quick to denounce liberal critics, accusing them of "playing politics" with the tragedy. She added that she was saddened by "the irresponsible statements from people attempting to apportion blame for this terrible event".
This discord dominated the media, but lost to both sides was that, to a degree, they were both right. On the one hand, Mrs Palin was not responsible for the acts of the man who carried out the attack, Jared Loughner. The political well has been poisoned by increasingly harsh rhetoric, but there does not appear to be any indication that Loughner was drinking at that well. He appears quite simply to be mentally deranged, not the follower of any political movement.
But while the shooting may have been apolitical, the aftermath was toxic. The partisan back and forth became more noticeable and jarring in the wake of the tragedy.
It was President Barack Obama who best put this sentiment into words. In his address at the memorial ceremony in Tucson, Mr Obama said: "At a time when our discourse has become so sharply polarised, at a time when we are far too eager to lay blame for all that ails the world at the feet of those who happen to think differently than we do, it is important for us to pause for a moment and make sure that we're talking with each other in a way that heals, not in a way that wounds."
The new Speaker of the House, John Boehner, responded thoughtfully as well. Mr Boehner postponed a congressional vote to repeal the recently passed health-care reform bill and called on the entire US Congress to be more civil and respectful in debate. There have been signs that politicians have been more temperate in their statements since.
The question, of course, is will this last. Which instinct will dominate in the future? Will politicians remain civil and respectful, listening to their better sides, or after a decent interval will they return to all-out warfare?
A recent poll conducted by Zogby International shows the public to be somewhat cynical. We asked whether people "believe that the shootings ... will lead to more moderation in the language and images politicians use"? Only 4 per cent said "this is a turning point" and "politicians will raise the level of respect". Thirty-four per cent believed that rhetoric will be moderated "but only in the short term", while 47 per cent said "there will be no change".
Based on America's past experiences of tragedy and hope, my sense is that the public may be both right and wrong. What is true is that those landmark events - from assassinations to milestone diplomatic moments - left positive legacies as well.
American politics may once again degenerate into ugly partisan bickering. Washington may fail to pass needed reforms on gun control and dealing with mental illness. But I believe that we have seen the last of the "cross-hairs" advertisements and gun imagery in politics.
And I believe that Ms Giffords will long remain a symbol reminding her colleagues and the country of the horror of this shooting and the need to remain civil and respectful in debate.
James Zogby is the president of the Arab American Institute