TUCSON - President Obama comforted a community suffused with grief and summoned the nation to recommit to a more civil public discourse as he delivered a eulogy Wednesday evening urging Americans to talk with each other "in a way that heals, not in a way that wounds."

Evoking memories of the six killed here Saturday, Obama seized upon the mass shooting at a congresswoman's supermarket meet-and-greet to tackle directly the subject of the nation's harsh political dialogue. He sharply decried the "politics and point-scoring and pettiness that drifts away with the next news cycle."

"Rather than pointing fingers or assigning blame, let us use this occasion to expand our moral imaginations, to listen to each other more carefully, to sharpen our instincts for empathy, and remind ourselves of all the ways our hopes and dreams are bound together," Obama told 14,000 people at the University of Arizona's McKale Memorial Center.

Obama did not ascribe a political motive to the alleged shooter, or suggest that either party was to blame. Rather, in a 33-minute speech, he sought to move the nation past the tragedy.

Accompanied at the arena by first lady Michelle Obama, the president said he joins Tucson in its grief, that he came here "as an American who, like all Americans, kneels to pray with you today and will stand by you tomorrow."

After touching down under blue skies and a bright desert sun, Obama paid a surprise visit to victims recovering at University Medical Center, including Rep. Gabrielle Giffords (D-Ariz.), who was shot in the head and remains in the intensive care unit.

A short time after the president left her room, Giffords, surrounded by her husband and three close friends from Congress - House Minority Leader Nancy Pelosi (D-Calif.), Rep. Debbie Wasserman Schultz (D-Fla.) and Sen. Kirsten Gillibrand (D-N.Y.) - opened her eyes and reached for her husband, showing a level of responsiveness that thrilled her loved ones.

"Gabby opened her eyes," said Obama, who was told about the incident by Giffords's husband during the short ride from the hospital to the arena. "And I can tell you she knows we are here, she knows we love her, and she knows we are rooting for her"

In Washington, lawmakers still unnerved by the assassination attempt on one of their own offered a display of bipartisan unity. More than 120 Democrats and Republicans went to the well of the House to pay tribute in moving and sometimes tearful speeches. The House unanimously approved a resolution late Wednesday condemning the attack and praising the rescue work of citizen and emergency responders.

Meanwhile, federal and local investigators sought to determine how suspect Jared Lee Loughner came upon the money to buy the weapon and ammunition he allegedly used in Saturday's rampage, parts of which were captured on the supermarket's security camera.

Judge Larry A. Burns of the Southern District of California was appointed to hear Loughner's case after federal judges in Arizona recused themselves because of their personal relationships with one of the victims, Judge John M. Roll.

The hopes of the nation were on Tucson, a shaken desert city that all week has mourned the fallen in hushed churches and at makeshift vigils. The first in a string of funerals - this one for 9-year-old Christina Taylor Green - begin Thursday.