Today is big showdown day in Philadelphia, the City of Brotherly Love. At 11:00 a.m., Barack Obama will be delivering his speech about Jeremiah Wright and racism, and it's do-or-die time:

Democrats who worry that Barack Obama is untested can put their concerns to rest.

The inflammatory rhetoric of the Rev. Jeremiah Wright has confronted Obama with the most severe test of his presidential campaign and, quite likely, of his public career.

He is now facing a full-blown and fast-moving political crisis in which his reputation as a leader with a singular ability to transcend racial divisions and unite Americans is in jeopardy.

A convergence of factors -- a media firestorm, a Democratic rival eager to exploit his stumbles and, most of all, a Republican opposition eager to rough up the man they expect to face in the general election -- have raised the stakes to new heights for Obama with the speech he will deliver in Philadelphia on Tuesday morning.

A successful address would go a long way toward answering Hillary Rodham Clinton's complaint that Obama has never shown he can handle the rough-and-tumble nature of modern political combat.

A failure could leave many of the white independent voters -- a key group behind Obama's swift rise in national politics -- doubting whether he is really the bridge-builder and healer he has portrayed himself to be.

While Richard Cohen wants to know what took Obama so long to address the Wright issue, what I want to know is:

What took the Clintons so long to bring it to the forefront?

Old video footage can hardly be called "newly discovered evidence" and the Clintons and their operatives are seasoned pros, who've surely known about this for a long time. Why now? Why not months ago, when Obama could have been derailed before his solid winning streak?

I don't know. But as timing is everything in politics, I suspect the Clintons did not want to give Obama a "Sister Souljah" opportunity which might have made them look bad and made him look good. As it is now, Obama looks like a backpeddling imposter, so the damage to him is incalculably worse, yet too late. Might they be trying to ensure his loss against McCain in order to ensure their spot at the top in 2012? Is a Democratic defeat now in loser Hillary's interest, just as a Kerry defeat was in her interest in 2004?

Or might the forever-stalled release of Clinton library documents and tax returns have something to do with it? From the Examiner:

....Clinton is uniquely positioned to demonstrate good faith by delivering on her promised openness now, instead of after the election. Her first step should be clearing the path for journalists, academics and other researchers seeking access to the millions of key Clinton administration documents hidden in the Clinton presidential library.

The documents can shed needed light on her role during her husband's administration in such controversies as the White House travel office firings, her health care task force's flouting of federal public meetings laws, and her directives in the aftermath of Vince Foster's death.

The Examiner continues

Also, she should let the sun shine now on documents concerning her weekly meetings with officials from the White House counsel's office and the Justice Department to vet judicial nominees. And she should open access to all documents on her role in foreign policy decisions concerning Kosovo, Bosnia-Herzegovina, Northern Ireland and Rwanda.

Step two is to release all of her tax returns, as is customary for serious presidential candidates. Step three is to make public all donor names to the Clinton library and foundation. Anything less than these three immediate steps, and Clinton's open government promises won't mean a thing to anybody except gullible journalists who accept them at face value.

All eyes are on Obama to do the "Wright" thing.

Sigh. Another day, another national media pageant. And another cynical blog post.

(I almost feel like accusing the script writers of having a dark sense of humor, but that would be wrong....)