Michelle Obama will address a throng of enthused Democrats in Denver tomorrow night. I trust she will not spend time detailing her slow evolution toward pride in her country.

On Tuesday night, Hillary Clinton will stir the crowd into a frenzy. I doubt she will wax nostalgic about dodging sniper bullets in Bosnia.

On Wednesday night, Bill Clinton will bathe in a wave of appreciation from thousands who still worship him. I assume by then he will have brought his months of pouting to an end.

In short, by the time Barack Obama takes the stage Thursday night at Invesco Field at Mile High, his opening acts will have been on their best behavior. Mrs. Obama's gaffe, Mrs. Clinton's fable and Mr. Clinton's intermittent tantrums all will have faded into memory.

Still fresh in America's minds, however: the nominee's weak performance last weekend at Rick Warren's Saddleback Church. On that stage, speaking extemporaneously – as he will do a month from now in the first presidential debate – viewers again learned that oratorical skill does not exactly bring a conjoined gift of off-the-cuff quickness.

John McCain was, by comparison, twice as comfortable, twice as responsive and as such, at least twice as presidential. In fairness, he was also at least twice as popular among the largely conservative audience.

This placed Mr. Obama in a bind: How exactly do you sugarcoat a radical abortion rights stance in front of a staunch pro-life crowd? His chosen answer was to hem and haw for an uncomfortable spell, concluding eventually that the decision on when life begins is "above my pay grade."

He will face no such challenges Thursday night. His every word will electrify the 75,000 in attendance. Among millions of TV viewers, Democrats will begin to smell victory while Republicans will wonder what their nominee can do to top it next week.

The answer, of course, is nothing, and the good news for McCain supporters is that his campaign knows it.

The Republican plan is to follow the political pyrotechnics of Denver with an understated grownups-in-charge mood that could well be a relief after the high-altitude adrenaline rush of the previous week.

At the Xcel Energy Center in St. Paul, Minn., the nominee will roll into town buoyed by a changing tide. The war is going better. The economy shows signs of a turnaround. America wants more energy exploration, a fundamental GOP issue.

Throw in the smackdown at Saddleback, and John McCain, whose primary campaign looked dead until a late-winter resuscitation, may be staging another against-the-odds comeback that will mature through September and October.

He actually seems to be listening to the party base he once regularly alienated; witness the purging of the thoroughly unsatisfactory Tom Ridge from his running mate list last week. Witness his five-word answer to Rick Warren – "from the moment of conception" – that made the Obama answer on when life begins look like the tap-dancing of a very ordinary politician.

In Denver, the sun sets over the Rocky Mountains. That sun will shine brightly for the Democratic nominee this week as he enjoys his last few days of unfettered adulation. But by Friday, as attention turns immediately to the Republican convention, the sun may also set on the eight months of Obama-mania.

This does not mean his poll numbers will plunge or the media will scale back the 3-to-1 coverage advantage they have granted him since he and Mr. McCain became the likely nominees.

But the election will enter the home stretch. A McCain campaign that saw its "celebrity" ad strike a nerve will hammer away at the concept, making sure to spend at least as much time talking about why Mr. McCain should be president as why Mr. Obama should not.

The Obama ascendancy has been remarkable. History has been made, no matter how the election turns.

But after Thursday night, there will be no more screams from full stadiums of fans. No more gushes of awed adoration from the packed streets of European capitals. It will be time for him to brace for three hazards – an awakened McCain campaign, a media community mildly embarrassed by its fawning, and an electorate that will finally pay sufficient attention to ask whether there is anything behind those pretty platitudes of hope and change.

Mark Davis is heard weekdays from 8:30 to 11 a.m. on WBAP-AM, News/Talk 820. His e-mail address is mdavis@wbap.com.