When Senator announced in early July that he would give his nomination address in an outdoor stadium in front of 75,000 people, he wowed members of both parties who saw it as an inspired stroke of campaign image making.
But as he landed here on Wednesday and prepared to become the first presidential candidate in nearly 50 years to accept his party’s nomination on such a big stage, the plan seemed as much risky as bold.
With daunting challenges of logistics, style and substance, the plan was hatched before the Republicans began a concerted drive to paint Mr. Obama as a media sensation lacking the résumé to be president. Now Obama aides are feeling all the more pressure to bring a lofty candidacy to ground level, showing that Mr. Obama grasps the concerns of everyday Americans.
On Wednesday, workers were still making changes to Invesco Field, home to the Denver Broncos, so it would feel more intimate, less like the boisterous rallies that served Mr. Obama so well early in the primaries, but also created the celebrity image that dogs him.
They were still testing camera angles, so Mr. Obama would appear among the giant crowd, not above it. They took steps to reduce the echo effect, familiar to football fans, of speaking in such a cavernous space. Planners scrapped their idea to turn the audience of 75,000 into a giant phone bank, in response to fears that the cellphone system would crash (people will instead be asked to text-message friends and neighbors to support the campaign, program aides said would be effective nonetheless.)
And workers put the finishing touches on the backdrop: faux columns intended to suggest a federal building in Washington and create an air of stateliness. (The McCain campaign named it the Temple of Obama, a label repeated by some commentators.)
Mr. Obama shared his rationale for the move when he took the stage at the Pepsi Center on Wednesday night. “We’re going to be moving to Mile High Stadium tomorrow, and I want to let you know why,” he said. “We want to open up this convention to make sure that everybody that wants to come can join in the party and join in the effort to take America back.”
Yet for Mr. Obama, the dramatic setting of the speech, which will take place between 10 and 11 p.m. Eastern time, stands in contrast to the “workmanlike” message he intends to offer.
“I’m not aiming for a lot of high rhetoric,” he said Wednesday. “I am much more concerned with communicating how I intend to help middle-class families live their lives.”
Mr. Obama holed up in a Chicago hotel over the weekend, and worked on the address well into the night this week with a small group of aides. He has studied several acceptance speeches, including ’s in 1992, ’s in 1980 and ’s in 1960.
Some aides worried about the setting overwhelming the message. But those closest to the planning said they had no regrets and were sticking to the sort of big-event politics that no other candidate has been able to match this year.
“We are leaning into this, how can you not?” said Jenny Backus, a campaign strategist working on the convention plan. “This is the enthusiasm gap,” referring to what polls show as excitement for Mr. Obama that Senator ’s campaign has not matched.
Dee Dee Myers, a former press secretary to President Clinton, said that delegates in the hall were excited about the stadium event but that it was the party’s senior strategists who were more wary of the setting.
“There’s a concern in the campaign about how do you pull this off in a way that makes it about the economic themes they want to hit,” Ms. Myers said. “He needs to get from the stadium to the diner, and it’s a hard thing to pull off.”
Mr. Obama’s aides had hoped to upend the traditional convention style. But the prolonged primary fight with Senator left the convention in the hands of the party’s career planners. Their flashy stage design, which has been likened to an arcade, had none of the look or feel of the more spare style of the Obama brand.
When a close circle of his top advisers presented Mr. Obama with $6 million plans to move his acceptance speech to the football stadium in early July, the candidate asked one question, said Anita Dunn, a senior strategist: “Will it rain?” The campaign produced a raft of meteorological data showing it had rained on Aug. 28 only once in 20 years. (Aides were alarmed, however, to arrive in Denver on Sunday to news of a nearby tornado.)
Peter Gage, one of the Obama planners, said he studied photographs of Kennedy’s speech at the Los Angeles Memorial Coliseum, the only other such address to be held in an outdoor stadium in the modern television era.
Mr. Gage said the circular stage in Denver was inspired by Kennedy’s. A Sky Cam above the field will provide bird’s-eye views. Mr. Obama’s family will sit on seats on the floor before him, along with voters from swing states. The goal is to highlight ordinary people, and then mobilize them to work for the campaign.
The Obama campaign dismissed Republican attempts to turn the night against them.
“I know that Senator McCain and his people are shooting barbs on the opulence of our convention from the mountaintop in Sedona from the McCain estate,” said David Axelrod, the campaign’s chief strategist. “I don’t think it warrants a response.”
This story, , first appeared in The New York Times.