At his best, Barack Obama is a leader who appeals to our better angels, who rode to the White House on a campaign of "hope." Nowhere was Obama’s empathy more needed, and more appropriate, than in Tucson Wednesday night. "If this tragedy prompts reflection and debate, as it should, let’s make sure it’s worthy of those we have lost," the president said. He led by example in a powerful, emotional and poetic address. He consoled not only those grieving in Arizona, but tried to unify the "American family, 300 million strong."

Said the president:

"When a tragedy like this strikes, it is part of our nature to demand explanations—to try to impose some order on the chaos, and make sense out of that which seems senseless. Already we’ve seen a national conversation commence, not only about the motivations behind these killings, but about everything from the merits of gun safety laws to the adequacy of our mental health systems. Much of this process, of debating what might be done to prevent such tragedies in the future, is an essential ingredient in our exercise of self-government.

"But 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 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 a way that wounds."

The contrast between Obama’s stirring and spiritual rhetoric, and today’s bizarre and defensive video by Sarah Palin, could not have been more striking. "What we can’t do is use this tragedy as one more occasion to turn on one another," Obama said. "As we discuss these issues, let each of us do so with a good dose of humility. 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."

Perhaps the most memorable part of the speech came when Obama disclosed that he’d just visited Gabrielle Giffords in the hospital and "Gabby opened her eyes for the first time." There were wild cheers inside the auditorium, accompanied by a stream of tears from those watching at home.

At some point soon Obama must tackle the tough questions resulting from the horrific shooting in Arizona: was it only a matter of time before a horribly violent incident occurred, given the current political climate? Did the extreme rhetoric on the right contribute to that culture? What can we do to prevent the next Tucson?

He’ll have ample time in the coming weeks, especially with the State of the Union address on January 25, to address how to restore tolerance and dignity in America, both in terms of our words and our laws. But first, we needed some closure on this tragedy, to help heal what are still very open wounds.

Speaking of 9-year-old Christina Taylor Green, Obama said: "I want our democracy to be as good as she imagined it." Tonight was a good start.