Barack Obama launched his historic fall campaign for the White House on Thursday with an outdoor Democratic National Convention extravaganza that blended old-fashioned speechmaking, Hollywood-quality stagecraft and innovative, Internet age politics. One day after becoming the first black man to win a major party presidential nomination, Obama readied the most important speech of his improbable candidacy, a prime-time address to an estimated 75,000 inside Denver's NFL stadium and uncounted millions watching at home on television.
Aides pledged a direct conversation with voters about the choice between Obama, a 47-year-old Illinois senator, and his Republican rival, Sen. John McCain of Arizona.
In an audacious move, McCain worked to steal at least a portion of the political spotlight by stoking speculation that his selection of a vice presidential running mate was imminent. An aide said McCain had made his decision, and one man on the short list, Gov. Tim Pawlenty of Minnesota, canceled all public appearances, raising attention even higher.
McCain is expected to announce his pick soon and appear with the person at a rally in Dayton, Ohio, on Friday.
The Republican convention opens Monday in St. Paul, Minn.
To the west, in the shadow of the Rocky Mountains, thousands waited in bright sunshine to gain admission to Invesco Field at Mile High, the stadium that had been turned into Obama's soundstage for the night at an estimated cost of $5 million.
By happenstance, the evening coincided with the 45th anniversary of Martin Luther King Jr.'s "I have a Dream Speech" on the steps of the Lincoln Memorial in Washington.
Obama's aides were interested in a different historical parallel - Obama was the first to deliver an outdoor convention acceptance speech since John F. Kennedy did so at the Los Angeles Coliseum in 1960.
The list of entertainers ran to Jennifer Hudson, the Academy Award winning performer singing the national anthem, and will.i.am, whose Web video built around Obama's "Yes, we can" rallying cry quickly went viral during last winter's primaries.
In a novel bid to extend the convention's reach, Obama's campaign decided to turn tens of thousands of partisans in the stands into instant political organizers. The plan called for them to use their cell phones to send text messages to friends as well as call thousands of unregistered voters from lists developed by the campaign.
Three hours before the day's program began, as many as 1,000 people were lined up at a pedestrian entrance to the stadium on a hot sunny day. Nearby street parking was going for as much as $80 a space.
In all, Obama's high command said it had identified 55 million unregistered voters across the country, about 8.1 million of them black, about 8 million Hispanic and 7.5 million between the ages of 18 and 24.
All are key target groups for Obama as he bids to break into the all-white line of U.S. presidents and at the same time restore Democrats to the White House for the first time in eight years.
The Democratic man of the hour paid a brief visit to members of his home-state Illinois delegation before the curtain went up on his show. "I came by (because) I had this speech tonight. I wanted to practice it out on you guys. See if it worked on a friendly audience," he joked.
There was no joking about the stakes in the speech, a once-in-a-campaign opportunity to speak to millions of voters who have yet to make up their minds between McCain and him. The polls show a close race nationally, with more than enough key battleground states tight enough to tip the election either way.
Obama's hopes of victory rely on holding onto the large Democratic base states such as California, New York, Michigan and his own Illinois, while eating into territory that voted for George W. Bush. Ohio tops that list, and Democrats have also targeted Montana, North Dakota, Virginia and New Mexico, among others, as they try to expand their Electoral College map.
His new running mate, Sen., Joseph Biden of Delaware, was brutally frank about the Democrats' chances in an appearance before one state's delegation. "This is not hyperbole: We cannot win without Pennsylvania," he said.
Polling shows the race for that state's 21 electoral votes close. Both the two previous Democratic candidates, Al Gore and John Kerry carried Pennsylvania over Bush.
Biden, who was born in Scranton, Pa., and represents a state that shares a border with Pennsylvania, is expected to spend large amounts of time campaigning in the state over the next several weeks.
McCain was in Ohio as Obama spoke, and after a series of sharply negative convention week television commercials, his campaign aired a one-night advertisement that complimented Obama and noted the speech occurred on the anniversary of King's famous address.
"Senator Obama, this is truly a good day for America. Too often the achievements of our opponents go unnoticed. So I wanted to stop and say, 'Congratulations,"' McCain says in the ad.
"How perfect that your nomination would come on this historic day. Tomorrow, we'll be back at it. But tonight Senator, job well done."