Four days after a gunman opened fire on a congresswoman and her constituents in Tucson, President Barack Obama joined thousands of Arizonans at an emotional memorial service Wednesday, counseling them and the rest of the nation to remember the fallen in ways that heal instead of wound.

Obama pleaded with Americans to set aside petty finger-pointing and instead raise the level of discourse to one "worthy of those we have lost." He eulogized the six people who died and praised the courage of the survivors, including U.S. Rep. Gabrielle Giffords, whose steady recovery seemed to buoy the grieving.

The memorial service, held in the University of Arizona's basketball arena, welled with emotion at times, but at other times resembled a political rally, with the audience cheering appearances by Gov. Jan Brewer, Homeland Security Secretary Janet Napolitano and Attorney General Eric Holder.

Obama, who visited with relatives and victims before the service, stuck uncharacteristically close to his prepared remarks for the first few minutes of his speech. But his demeanor, and the mood of the crowd, changed considerably when he revealed that, shortly after he visited the gravely wounded Giffords at University Medical Center, "she opened her eyes for the first time."

"She opened her eyes," he said. "She knows we're here and she knows we love her."

The McKale Memorial Center crowd, estimated at 13,172, erupted in cheers as Giffords' husband, Mark Kelly, received hugs from first lady Michelle Obama and Napolitano, who flanked him in the front row.

Obama's voice also seemed to waver slightly at mentions of Christina Taylor Green, the 9-year-old girl killed in the rampage north of Tucson. The president's younger daughter, Sasha, was born just three months before Christina.

"She was off to meet her congresswoman, someone she was sure was good and important and might be a role model," Obama said of Christina. "She saw all this through the eyes of a child, undimmed by the cynicism or vitriol that we adults all too often just take for granted."

The memorial service aired on television and radio nationwide and came amid an increasingly shrill debate over the shootings and whether the gunman was motivated by violent imagery or harsh political language. Many people were watching Obama to see how he would react to the rancor.

He urged calm and reflection and urged Americans not to "use this tragedy as one more occasion to turn on each other."

Those were the right words, according to longtime Arizona political scientist Bruce Merrill, who called the speech powerful.

"The question is when the sun comes up the next morning, is it back to politics as usual?" said Merrill, an Arizona State University professor emeritus. "Given the harsh realities of the world we live in, in the long run I doubt that it would have much of a long-lasting kind of an effect. I wish it would, but I would be surprised if it does."

The speech was well-received in Tucson, where the event seemed to electrify the community and the UA campus. People stood in line all day Wednesday - a few showed up Tuesday night - and by late afternoon, university officials decided to show the service on the jumbo screens at nearby Arizona Stadium, where an overflow crowd of 13,000 gathered.

Security was understandably tight, with metal detectors, bomb-sniffing dogs and police, a sharp contrast to the informal gathering that left Giffords exposed to the deadly rampage outside a Safeway store on Saturday.

Inside the arena, a who's who of politics gathered in the front rows: the president and first lady, Brewer, Napolitano, Holder, Supreme Court Justice Anthony Kennedy, former Supreme Court Justice and Arizonan Sandra Day O'Connor, Sens. Jon Kyl and John McCain, and almost all of the state's congressional delegation.

Seated among them - between Obama and O'Connor - was UA junior Daniel Hernandez, the intern who is credited with saving Giffords' life when he ministered to her at the shooting scene. He insisted he was not a hero, that others deserved the accolade more, but Obama in his speech told Hernandez his acts reflected the courage of a hero.

Hernandez received several standing ovations during the service.

A solemn Brewer praised Hernandez and spoke of the losses suffered by Arizonans in the shooting. But she said the state would be unbowed as it dealt with those losses.

"Arizona is united in a mission of recovery," she said. "This state, bound together by prayer and action, hope and faith, will not be shredded by one madman's act of darkness."

Obama used much of his speech to talk about the victims, those who died, those who survived and those who reacted to protect others.

"These men and women remind us that heroism is found not only on the fields of battle," he said. "They remind us that heroism does not require special training or physical strength. Heroism is here, all around us, in the hearts of so many of our fellow citizens, all around us just waiting to be summoned."

But his most pointed remarks were directed at the angry rhetoric that erupted within hours of the shooting.

"At a time when our discourse has become so sharply polarized, at a time when we are far too eager to lay the blame for all that ails the world at the feet of those who happen to think differently than we do, it's important for us to pause for a moment and make sure that we are talking with each other in a way that heals, not in a way that wounds," he said.

Attempts by either side to assign blame for the shootings or to ascribe motive to the gunman will lead to nothing good, he said, but good can come from a healthy discussion.

"Let us remember that it is not because a simple lack of civility caused this tragedy - it did not - but rather because only a more civil and honest public discourse can help us face up to our challenges as a nation," he said.

He said Americans should be civil "because we want to live up to the example of public servants like (U.S. District Judge) John Roll and Gabby Giffords, who knew first and foremost that we are all Americans, and that we can question each other's ideas without questioning each other's love of country."

Obama stopped at University Medical Center for about 45 minutes to visit some of the victims of the shooting. He spent almost 10 minutes with Giffords and Kelly, shortly before she opened her eyes for the first time.

That news drew applause and tears at the service and lent Obama's speech a new layer of emotion, which grew as he talked about the other victims. He returned near the end to young Christina, whose story has captured the nation.

"I want to live up to her expectations," he said. "I want our democracy to be as good as Christina imagined it. All of us, we should do everything we can to make sure this country lives up to our children's expectations."

Odelia Celaya, 64, of Tucson, who brought her 14-year-old granddaughter to the ceremony, said she walked into the stadium feeling angry about the shooting. But she said the president's speech eased her angst.

"He changed the way we were thinking," she said. "There was a lot of hatred and he made us realize that is not the way to be."

Republic reporters Dan Nowicki, Ronald J. Hansen and Richard Ruelas contributed to this story.

LINK TO VIDEO:

http://www.azcentral.com/video/748635384001