Barack Obama reinvents the dream of Luther King

Barack Obama staked his claim for the White House by saying he could revive the American dream.

The Democrat candidate for the presidency launched his formal campaign in a 45-minute speech which was hailed immediately as one of the greatest in American political history.

With echoes of John F Kennedy and Martin Luther King - who made his " I have a dream" speech exactly 45 years ago - Mr Obama told a 75,000-strong crowd in Denver, Colorado, last night that the election was a chance to bring change to a country tired of eight years of George Bush.

He hinted that Republican rival John McCain's age was his weakness, repeatedly using the future as a theme to emphasise the gulf between their ages. Mr Obama is 47, Mr McCain is 73.

Mr Obama called on the American people to reject the Republicans on election day. "On November 4th," he said, "we must stand up and say: 'Eight is enough.'"

Joined on stage by his wife Michelle, daughters Malia and Sasha and running mate Joe Biden, he was given a rapturous ovation by the crowd.

He was greeted by soccer style chants of "O-ba-ma" and "yes we can" as he calmly waited for the cheering to subside and accept formally accept his party's nomination.

Millions watched the speech on live television at the prime time of 9pm on the East coast.

After talking about ordinary Americans, from young soldiers to students, he outlined his vision for change.

"It is on their behalf that I intend to win this election and keep our promise alive as president of the United States," he said.

"What is that promise? It's a promise that says each of us has the freedom to make of our own lives what we will, but that we also have the obligation to treat each other with dignity and respect."

His main theme was to link Mr McCain to the highly unpopular Bush administration, a tactic which is to form the centrepiece of his strategy for victory in November. "America, we are better than these last eight years," he said.

"This moment, this election, is our chance to keep, in the 21st century, the American promise alive.

"We are here because we love this country too much to let the next four years look just like the last eight. Don't tell me that Democrats won't defend this country. Don't tell me that Democrats won't keep us safe.

"The Bush-McCain foreign policy has squandered the legacy that generations of Americans - Democrats and Republicans - have built, and we are to restore that legacy."

Campaign aides said to prepare for the biggest speech of his life Mr Obama had studied acceptance speeches from John F Kennedy, Ronald Reagan and Bill Clinton.

With the theme of the night Change You Can Believe In, Mr Obama launched into his vision for America.

He began by paying tribute to his family and his opponent Hillary Clinton and her husband, former president Bill, whose presence had sometimes overshadowed the start of the convention.

He said America was at a crossroads because of war and the faltering economy. "We meet at one of those defining moments - a moment when our nation is at war, our economy is in turmoil and the American promise has been threatened once more," he said.

"Tonight, more Americans are out of work and more are working harder for less. More of you have lost your homes and even more are watching your home values plummet.

"More of you have cars you can't afford to drive, credit card bills you can't afford to pay, and tuition that's beyond your reach.

"These challenges are not all of government's making. But the failure to respond is a direct result of a broken politics in Washington and the failed policies of George W Bush.

"America, we are better than these last eight years. We are a better country than this."

Mr Obama said Democrats had to seize the opportunity to eject an unpopular government. He said the US was saddled with a war few people want and a failing economy with millions hurt by the credit crunch. He added that Mr McCain would be no better than Mr Bush.

But the speech was sketchy on policy. He talked about cutting taxes for most Americans, ending tax breaks for "corporations that ship jobs overseas" and ending dependence on Middle Eastern oil, as well as a theme of education.

"America, now is not the time for small plans," he said. "Now is the time to finally meet our moral obligation to provide every child with a world-class education, because it will take nothing less to compete in the global economy.

"Michelle and I are only here tonight because we were given a chance at an education. And I will not settle for an America where some kids don't have that chance. I'll invest in early childhood education. I'll recruit an army of new teachers, and pay them higher salaries and give them more support. And in exchange, I'll ask for higher standards and more accountability.

"And we will keep our promise to every young American - if you commit to serving your community or your country, we will make sure you can afford a college education."

Mr Obama also promised affordable health care for all Americans and equal pay for men and women. To cheers from the crowd, he vowed to end the war in Iraq, defeat the Taliban in Afghanistan and tackle al Qaeda.

"As commander in chief, I will never hesitate to defend this nation, but I will only send our troops into harm's way with a clear mission and a sacred commitment to give them the equipment they need in battle and the care and benefits they deserve when they come home," he said.

"And I will restore our moral standing, so that America is once again that last, best hope for all who are called to the cause of freedom, who long for lives of peace, and who yearn for a better future."

Mr Obama also touched on fears people might have about a black man in charge of the nation and one with little political experience.

He said: "I get it. I realise that I am not the likeliest candidate for this office. I don't fit the typical pedigree, and I haven't spent my career in the halls of Washington. What the naysayers don't understand is that this election has never been about me. It's been about you.

"For 18 long months, you have stood up, one by one, and said enough to the politics of the past. You understand that in this election, the greatest risk we can take is to try the same old politics with the same old players and expect a different result.

"You have shown what history teaches us - that at defining moments like this one, the change we need doesn't come from Washington. Change comes to Washington.

"Change happens because the American people demand it - because they rise up and insist on new ideas and new leadership, a new politics for a new time.

"America, this is one of those moments. I believe that as hard as it will be, the change we need is coming."

The speech was greeted by his supporters as brilliant, while Republican commentators concentrated on its lack of substantive policy rather than attacking the rhetoric, which they know Mr McCain will be unable to match.

Chat show host Oprah Winfrey said: "I think it's the most powerful thing I have ever experienced. He's not an African-American candidate," she said. "He's a candidate for Americans."

Independent commentator Walter Shapiro wrote in online magazine Salon.com: "Win or lose in November, America has been reshaped forever by this alliance of what Obama described as 'young people who voted for the first time and the young at heart."