| TUCSON, Arizona
TUCSON, Arizona President Barack Obama mourned victims of an Arizona shooting spree on Wednesday and urged Americans not to let a political debate over the tragedy be used as "one more occasion to turn on one another."
In an emotional address to thousands of people who packed a Tucson memorial service, Obama said no one knew what prompted a gunman to go on a rampage that killed six people and critically wounded Representative Gabrielle Giffords. He warned against seeking "simple explanations" and cautioned Americans not to place blame.
"None of us can know with any certainty what might have stopped those shots from being fired, or what thoughts lurked in the inner recesses of a violent man's mind," Obama said.
Jared Lee Loughner, 22, has been charged with firing at Giffords and others gathered in a Tucson shopping center parking lot last Saturday where the 40-year-old Democrat Giffords was hosting a meet-and-greet for constituents. Among those killed were a federal judge and an aide of Giffords.
Obama, who as president has sometimes had difficulty making an emotional connection with Americans, faced the challenge of comforting Americans, helping the community heal and bringing people together.
He may have succeeded best by citing the example of 9-year-old Christina Taylor Green, who was born on September 11, 2001, the day of the hijacked plane attacks on the United States. Interested in government, she attended the Giffords event where she was shot and killed.
"I want us to live up to her expectations," Obama said. "I want our democracy to be as good as she imagined it."
The president leaped firmly into the political debate that broke out shortly after the gunfire ended last Saturday -- whether harsh political rhetoric from last year's acrimonious congressional elections had anything to do with inspiring the gunman to shoot.
"What we can't do is use this tragedy as one more occasion to turn on one another," Obama said.
OPENED HER EYES
Obama began his visit to Arizona by stopping at University Medical Center to see Giffords, who survived a gunshot to the head that traveled the length of her brain on the left side. He also visited four other patients wounded in the attack.
Obama brought roars of approval from the estimated crowd of 14,000 people inside a University of Arizona arena by saying he had been told that, shortly after he and his wife, Michelle, saw her, Giffords opened her eyes for the first time since the shooting.
"Gabby opened her eyes," Obama said. "So I can tell you she knows we are here, she knows we love her and she knows that we are rooting for her through what is undoubtedly going to be a difficult journey."
University of Virginia political science professor Larry Sabato said Obama achieved his goal.
"He did exactly what he was supposed to do. He stayed out of partisan politics and kept the focus on the victims and the families," he said.
The shooting rampage has fueled a debate about whether the heated partisan rhetoric featured in recent U.S. political campaigns can lead to violence. Politicians in both parties have suggested cooling the tone of discourse in Washington.
Prominent U.S. Republican Sarah Palin defended her fiery rhetoric on Wednesday but ignited a fresh controversy by accusing critics of "blood libel" in linking her to the shooting spree.
Palin has been a focus of criticism from the left since the shootings for urging followers to "reload," not retreat, after the healthcare debate and publishing an electoral map identifying vulnerable Democratic congressional districts, including Giffords', with rifle cross-hairs.
REFLECTION AND DEBATE
Both Democrats and Republicans have accused each other of overheated rhetoric in the aftermath of the tragedy.
Obama said if the deaths helped usher in a more civil public discourse, it could only be for the good.
"If this tragedy prompts reflection and debate, as it should, let's make sure it's worthy of those we have lost. Let's make sure it's not on the usual plane of politics and point scoring and pettiness that drifts away with the next news cycle."
In Washington, the House of Representatives condemned the shootings that gravely wounded Giffords, denouncing the "horrific attack."
House Speaker John Boehner, struggling to hold back tears, opened a day of speeches on the resolution saying, "We are called here to mourn an unspeakable act of violence ... these are difficult hours for our country."
In California, a Palm Springs man was arrested on Wednesday on charges of threatening to kill Democratic Representative Jim McDermott of Washington state.
According to the criminal complaint filed in U.S. District Court in Seattle, Charles Turner Habermann, 32, left two threatening, expletive-filled voicemail messages at the Seattle office of McDermott on December 10.
Law enforcement officials were piecing together more about Loughner and the events leading to the shooting that has brought multiple federal charges against him.
Just hours before the rampage, Loughner was stopped by an Arizona Game and Fish Department office for running a stoplight.
Authorities said Loughner received a verbal warning and was released.
(Additional reporting by Brad Poole in Tucson, Thomas Ferraro, Donna Smith, Jeremy Pelofsky and John Whitesides in Washington, Dan Whitcomb and Steve Gorman in Los Angeles, and John Goh in Singapore; Writing by Steve Holland; Editing by Peter Cooney)