Barack Obama's speech about race in America reflects a new stage of the political campaign. Call it hyper-scrutiny.

This stage usually begins when the field is reduced to the two contenders (this year, three) who have a realistic chance of becoming president. From now on, every word they utter, every action they take or have uttered or taken in the past will be subjected to unrelenting and unforgiving examination.

All candidates for president think they know what this stage will be like but they don't. Even the most seasoned campaigner is never fully prepared for the intensity of this spotlight. Ask Al Gore, who had run many times for public office and yet sighed his way through a debate with George W. Bush in 2000, aggravating his reputation for aloofness.

Obama's ties to Rev. Jeremiah A. Wright Jr. the incendiary pastor from his home church in Chicago have been hovering out there for months as a threat to his campaign. But his religious life only became a front-page story after Obama established a clear lead for the Democratic nomination.

That's why he felt compelled to speak out now, just as many Americans are learning about him for the first time. It would have been devastating to let Rev. Wright (who once said "God Bless America" should be sung as "God Damn America") define his views on race and country.

The stage of hyper-scrutiny is inevitable in any campaign, but this year there's a new twist: the first presidential election subject to the YouTube effect, when video clips like Rev. Wright's sermons are instantly and permanently available to any voter with a mouse and a finger.

Obama has shrewdly used this new-media environment to engage and energize a new generation of voters, so he understands that those tapes of his pastor will be circulated throughout the fall campaign, promoted and publicized by his opponents. That's why he had to inoculate himself against that virus now, before it spread too widely.

The country got a taste of the YouTube effect in 2006. Sen. George Allen was defeated after he used a racial slur, "macaca," and his insulting remark ricocheted around the Internet. Sen. Conrad Burns lost as well after video of him falling asleep at campaign events became a YouTube hit.

Senate campaigns are minor-league events compared to presidential politics. All three candidates who could take the oath of office next January have already learned how scorching the spotlight of hyper-scrutiny can be.

Obama's foreign-policy adviser, Samantha Power, had to resign after calling Hillary Clinton a "monster." Clinton supporter Geraldine Ferraro also bit the dust after arguing that Obama was benefiting from his race. John McCain's relationship with a female lobbyist became the subject of lengthy newspaper articles. None of those topics would have attracted nearly as much attention just a few months ago.

This week, during a Middle East tour, McCain faced embarrassing questions after stating that Iran was training Al Qaeda fighters. That's not true, but he has probably made the same mistake hundreds of times and nobody noticed or cared until now.

The spotlight of hyper-scrutiny is powered partly by news organizations, which are deploying squads of investigative reporters to excavate every detail about the surviving candidates. In 1992, after Bill Clinton clinched the Democratic nomination, Steve (then working for U.S. News & World Report) spent weeks examining the Arkansas governor's determined efforts to evade the draft during Vietnam. Only someone with a real chance at winning merits that kind of attention.

As Allen and Burns learned, even a momentary lapse can be fatal. Pictures of Michael Dukakis riding a tank, and John Kerry riding a windsurfer, exposed both Democrats to endless ridicule. And that was before YouTube.

Two other factors fuel this stage of intensive examination:

1) The opposition-research operations maintained by both parties. Now that they know their prime targets, they can focus their fire. If news organizations had not unearthed tapes of Wright's tirades, the GOP surely would have.

2) Technology. YouTube is part of a much larger trend on the Internet including blogs, Web sites and viral videos that vastly expands the outlets for investigation and criticism of the candidates. The spotlight of hyper-scrutiny is more revealing than ever.

There's a downside risk here to healthy political debate. A trivial issue, a tiny gaffe, can explode beyond reasonable proportions. But the pressures of the presidency are incalculable. And the stage of hyper-scrutiny tests and trains a candidate to survive them.

Steve Roberts' latest book is "My Fathers' Houses: Memoir of a Family" (William Morrow, 2005). Steve and Cokie Roberts can be contacted by e-mail at