For a people so obsessed with race, we are exceptionally bad at talking about it.

Some of us fear talking about it, get nervous and fluttery and act as if this is a topic polite people should avoid.

Some of us are unequipped to talk about it, too ignorant of the history that undergirds it, too willing to bend that history toward ideological ends, too blithely dismissive of the fact that history matters, that past informs present informs future.

Some of us lack the compassion to talk about it, prefer to use it only as a means of denigrating, diminishing and dismissing the Other.

Some of us are uncomfortable talking about it because it makes us feel what we'd rather not: anger, sorrow, defensiveness, guilt.

And some of us -- politicians in particular -- talk about race only to use it as a weapon, only as a means of hitting the other candidate.

Barack Obama spoke of race Tuesday in Philadelphia. He did so with calm confidence, with a firm grasp of, and appreciation for, the history that undergirds it, with compassion that did not stop at the color line and yet, without anger, sorrow, defensiveness or an attempt to impose guilt, without making it a political cudgel.

"Not this time, " he said.

"And so, " intoned Jon Stewart of The Daily Show, "at 11 o'clock a.m. on a Tuesday, a prominent politician spoke to Americans about race as through they were adults."

Obama, who has steadfastly refused to be defined or confined by race, has nevertheless seen race consume the last two weeks of his campaign.

First, there was Geraldine Ferraro and her asinine contention that Obama is somehow an affirmative action candidate, that the millions of black, white and other voters who support him are somehow bewitched by the color of his skin and never mind that Jesse Jackson, Al Sharpton and Alan Keyes have the same color skin, yet never enjoyed more than a fraction of his success.

More substantively, there was the Rev. Jeremiah Wright, Obama's friend and former pastor. Video clips (from what source, I still can't tell) flooded the Internet showing the pastor denouncing America in coarse and strident tones. As depicted in those excerpts, Wright, who is also an avowed admirer of the hateful Louis Farrakhan, crossed the line from the incendiary truth-telling of the African-American ministerial tradition into a corrosive, paranoid, ungodly bitterness.

For Obama, the expedient and politically intelligent thing would have been to denounce Wright, cut him loose and move on. Instead, he did what Clinton did not after Ferraro shot off her mouth, what President Bush did not after he spoke at Bob Jones University, what John McCain did not after he wimped out about the Confederate flag, what Ronald Reagan did not after he blessed "state's rights, " what Jimmy Carter did not after he invoked "ethnic purity."

He showed courage. He seized the teachable moment. Then he taught that moment, not in the stark and simplistic black and white terms so often preferred by blacks and whites but, rather, with a sophisticated grasp of the thorny nuances of race and a compassion vast enough to comprehend not only the anger and frustration of blacks, but also that of whites -- and to recognize the righteousness in both.

And Obama reminded us that anger and frustration are not destiny.

"America can change, " he said. "That is the true genius of this nation. What we have already achieved gives us hope, the audacity to hope, for what we can and must achieve tomorrow."

He explained America to itself. He pointed America toward higher ground. It was a brave, magnificent and -- mark my words -- historic moment.

You see, we just lost the last excuse for our inability to talk about race.

Last week in Philadelphia, Barack Obama showed us how.