For Obama, a questionable finale planned in Denver

Barack Obama will accept the Democratic nomination at Invesco Field at Mile High, a 76,000-seat stadium. (ASSOCIATED PRESS)

WASHINGTON - When Barack Obama accepts his party's nomination in the Broncos' football stadium - poised at one end zone, like John Elway preparing for a game-winning drive - the image may indeed provoke the associations that its planners hope to trigger.

Moving the convention finale in Denver from an indoor arena to a huge stadium, with a bigger crowd and more "real" people, will probably suggest a new, more democratic spirit. And having Obama speak in such a grand setting may give him a majestic, Cecil B. DeMille aura. And the whole scene could inspire commentators to point out that only once before has a nominee accepted his prize in a stadium - John F. Kennedy.

But the Kennedy comparison has already been made in so many ways that this extra echo feels insistent and unnecessary. And even if the stadium show next month accentuates some of Obama's strengths - he is, after all, a big figure, and this is a historic moment - some might still wonder why his campaign chose to drape something real in something so obviously contrived.

The answer seems to be that Obama, whose distinctive family background and upbringing made him seem like an authentic outsider during the primaries, is willing to sacrifice some authenticity for a little extra star appeal. The presidency is, after all, a grand stage, and one of Obama's strengths against John McCain is his larger-than-life persona. It conveys the sense that he, like Kennedy and Reagan and Roosevelt, is a force of destiny.

This force may be strong enough to propel him to the White House. But if so, it's better for Obama if voters feel it on their own, rather than see it advertised. McCain has been struggling to make a virtue out of his comparative ordinariness, by claiming that Obama is "all talk," meaning a lot of empty rhetoric. The charge hasn't really stuck because of Obama's serious manner, and his recent focus on economic issues, which has given his campaign a more grounded feel.

But last week's decision to jack up the stagecraft on his Aug. 28 acceptance speech by having it in a stadium helps make McCain's case for him. Instead of focusing on the substance of what Obama will be saying, the Democrats are calling special attention to where he's saying it.

Already, Obama's website is featuring a stadium logo and a sign proclaiming an "Open Convention," with anyone welcome to attend. (The Obama team undercuts its point a bit by offering anyone who gives more than $5 a chance at being one of 10 supporters to greet Obama backstage, like FM radio stations offering the 25th caller a chance to meet his or her favorite rock band.)

The stadium show might also remind voters that many of Obama's appearances during the primary season were carefully stage-managed, though in a less obvious way. His campaign often posed him next to state capitols and other grand monuments, sometimes having him enter the rally by striding purposefully down a marble staircase.

The image-making aspect of these appearances was obscured somewhat by the fact that the monuments were usually in the biggest squares in town. Obama was popular enough to attract thousands of spectators, so his choice of venue seemed to be driven by crowd size as much as backdrop.

And as the underdog running against the great Clinton machine, Obama was forgiven many of his excesses. (Hillary Clinton, by contrast, staged a lot of events in high-school and college gyms, her podium resting under folded-up basketball hoops while spectators sat in wooden bleachers, beneath Home of the Titans-style banners.)

But now, as the Democratic nominee and front-runner in most polls, Obama will be closely monitored for any signs of hubris. And, to be fair, it's hard to draw a line between the natural exuberance of his supporters and any signs of overconfidence or presumptuousness. As the election draws closer, their excitement is only going to build, and there will be lots of big rallies and a growing sense of historical portent.

"Make a donation now and you can have a front seat to history," his website proclaims.

But the historic nature of Obama's candidacy may be the best reason to keep it unpolluted by the usual political trappings. So far, his campaign hasn't concurred.

Peter S. Canellos is the Globe's Washington bureau chief. National Perspective is his weekly analysis of events in the capital and beyond.