Democratic National Convention

Barack Obama, launching his historic fall campaign for the White House with an outdoor Democratic National Convention extravaganza, pledged Thursday to "fix the broken politics in Washington" after he defeats Republican John McCain in the fall.

"We are better than these last eight years. We are a better country than this," Obama said in excerpts of his acceptance speech released in advance of his speech.

Seeking to weld his Republican rival to the outgoing Bush presidency, Obama declared that McCain as a senator had voted with Bush 90 percent of the time. "I don't know about you, but I'm not ready to take a 10 percent chance on change," he said.

"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," Obama said in the excerpts.

He said it's time to change leadership in Washington after two terms of the Bush administration. "On Nov. 4," he said, "we must stand up and say: 'Eight is enough."

Obama said that more Americans now are out of work or working harder for less, more have lost homes or are watching home values plummet, have cars they can't afford, credit card bills they can't pay and tuition that is beyond 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 presidency of George W. Bush," he said.

Obama said he was setting a goal "for the sake of our economy, our security and the future of our planet," of ending dependence on oil from the Middle East in ten years.

Playing on Bush's assertion in his 2007 State of the Union address that the nation was "addicted" to foreign oil, Obama said, "Now is the time to end this addiction."

Obama also sought to ease any concerns Americans might have that he was not prepared to be commander in chief or that Democrats were not as trustworthy as Republicans on national security.

"We are the party of Roosevelt. We are the party of Kennedy. So don't tell me that Democrats won't defend this country. Don't tell me that Democrats won't keep us safe," Obama said.

"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," he said.

"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.

Obama's convention finale 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 was delivering 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. McCain of Arizona, who is turning 72 this week.

McCain is expected to announce his pick soon and appear with the person at a rally in Dayton, Ohio, on Friday.