WASHINGTON: Sen. Barack Obama stormed into the backstretch of his historic race for the White House on Thursday, painting a sweeping vision of his confidence in America’s promise and reinforcing it with details of how he would restore America’s image overseas and the economy at home.

Obama fired up his old magic on Thursday night. His speech delivered almost more than any single speech could accomplish — a combination of poetry and prose aimed to put to rest questions about his candidacy, connect with undecided voters and hit the kind of emotional high notes that have thrilled his followers.

Obama, 47, the first African-American major-party presidential nominee, electrified the Mile High stadium in Denver with more than 80,000 cheering, flag-waving fans who came to hear his acceptance of the Democratic Party’s nomination with the promise that he would fix “the broken politics of Washington” after years of Republican rule.

With the grandeur of the Rocky Mountains as a backdrop, Obama declared that the “American promise has been threatened” by eight years under President George W. Bush, and that John McCain represented a continuation of the policies that undermined the nation’s economy and imperiled America’s standing around the world.

The McCain camp did its best to shift the spotlight from Obama yesterday morning by announcing that McCain selected Alaska Gov. Sarah Palin to be his vice presidential running mate, which — according to the McCain campaign — was a surprise pick meant to shake up the race and reinforce the idea of the Arizona senator as a reformer.

Obama left little doubt that he intended to press his campaign against McCain this fall. In cutting language, he linked McCain to what he described as the “failed presidency of George W. Bush.”

Obama was under considerable pressure to deliver a speech of special force and power. What he gave here was a combination of old and new — new toughness coupled with the message that got him this far.

“It’s time for them to own their failure,” he said of the Republicans. “It’s time for us to change America.”

Obama showed real fire, and directed it at his opponent, even on McCain’s signature issue — national security. Alternating between being evocative and pragmatic, the Illinois Democrat laid clear blame for his country’s current wartime predicaments of high gas prices, soaring deficits and failing mortgages on President Bush.

And, in an effort to silence critics who have called him all show and no substance, Obama laid out a lengthy list of policy prescriptions he would enact if elected president: Tax cuts for 95 percent of working families, a pledge to end dependence on foreign oil in 10 years through investment in natural gas, safe nuclear power, clean coal technology, more fuel-efficient cars and $150 billion investment in alternative energy.

He promised to improve education, pay teachers more, provide every American with affordable health care and protect Social Security’s financial future. “Barack Obama raises the prospect of a candidate for the first time being elected into the presidency almost wholly on the basis of a compelling persona,” said Wall Street Journal columnist Daniel Henninger. “It is no surprise this could happen in an age tugged by the siren sign of celebrity.

“The 2008 election is almost certainly going to be decided by white, lower-middle-class voters — the people who voted for Hillary Clinton this year and before that for Ronald Reagan. If these voters don’t swing behind the Obama candidacy in Ohio, Michigan, Florida and Missouri, he will lose.”

If it did nothing else, this week’s Democratic National Convention served as a reminder of the historical import of Obama’s nomination and the astonishing transformation of this country.

He is the product of an interracial marriage that was illegal in many parts of the country not long ago, and with his choice of Sen. Joe Biden as his running mate, little notice was taken of Biden’s Roman Catholicism. The Obama camp’s strategy was to define him as a “regular guy” with a humble background who understands the financial hardships facing middle-class families and portraying McCain as a continuation of the unpopular Bush administration.

Obama’s challenge between now and election day is to keep Americans focused on that mantra. He will use the 68-day sprint to the election finish line Nov. 4 to unleash a hard-hitting campaign attack that casts McCain as a well-heeled, aging war hero who is out of touch with most Americans.