With his party's nomination in hand, Sen. Barack Obama launched a historic general-election campaign by promising a middle-class economic renewal and tying his Republican opponent tightly to the record of the current president.

Barack Obama planned to make a hard pitch for his fitness as commander in chief and as a responsible steward of the nation's economy, according to advance speech excerpts, arguing that Republican rival John McCain would simply extend what Democrats consider the failed policies of President George W. Bush's administration.

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

The speech will be the culmination of the Democratic National Convention in Denver, delivered in a football stadium holding 75,000, packed with supporters. Sen. Obama used the speech to promise to energize the nation's middle class by restoring balance to the economy by junking the policies adopted by President Bush. The excerpts pushed the Democrats' main campaign strategy -- tying Sen. McCain to the unpopular Bush.

'John McCain has voted with George Bush 90% of the time,'' Sen. Obama said. 'Sen. McCain likes to talk about judgment, but really, what does it say about your judgment when you think George Bush was right more than 90% of the time?'

Known for the high ideas that characterize his most memorable speeches, Sen. Obama's nominating rhetoric was more methodical than usual in both substance and structure. Opening with a few biographical paragraphs about his Kenyan father and Midwestern mother, Sen. Obama moved quickly to a more prosaic recital of his platform and policy planks. In a speech that tilted heavily toward economic policy, Sen. Obama spoke of revamping the tax code and noted the problems caused by the current credit crisis and the high price of gasoline.

'The fundamentals we use to measure economic strength are whether we are living up to that fundamental promise that has made this country great a promise that is the only reason I am standing here tonight,'' Sen. Obama said.

Sen. Obama devoted a large portion of his speech to the price of oil and the threat of global warming, turning again to the campaign's policy book for energy independence. Sen. Obama offered a thumbnail sketch of that policy: $150 billion in government investments in alternative energy and a goal of creating five million new jobs. Again, he attacked his Republican rival for standing by passively as a senator while the nation increased its energy dependence.

'Washington has been talking about our oil addiction for the last 30 years, and John McCain has been there for 26 of them,' Sen. Obama said in the advance excerpts. 'And today, we import triple the amount of oil as the day that Senator McCain took office.''

`Sen. Obama also emphasized his fitness to be commander in chief and what he characterized as failures by Republicans to keep the nation safe. He pledged to end the war in Iraq and promised not to start unnecessary conflicts. '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,'' Sen. Obama said.

拿到了民主党总统候选人提名的巴拉克•奥巴马(Barack Obama)参议员发起了历史性的总统竞选战役，承诺要重振以中产阶级为主体的经济，并将竞争对手、共和党候选人麦凯恩(John McCain)与现任总统的政绩联系起来。

奥巴马在演讲中宣扬自己是适合担任美国统帅和打理美国经济的可靠管家，并宣称共和党竞选对手麦凯恩只会延续布什政府的政策。民主党认为这些政策非常失败。

奥巴马在丹佛向支持者发表讲话

奥巴马说，我们是罗斯福的政党、肯尼迪的政党。别跟我说民主党人不会保卫这个国家。别跟我说民主党人不能保护我们的安全。

奥巴马在一个可容纳75,000人的足球场发表了这次演讲，会场挤满了支持者，这也是在丹佛召开的民主党全国大会的高潮。奥巴马利用这次演讲的机会，承诺要废除布什采取的政策，恢复经济平稳，从而加强美国中产阶级的力量。演讲稿大力推行了民主党的主要竞选战略──将麦凯恩和不得民心的布什联系在一起。

奥巴马说，麦凯恩90%的时候都投票支持布什，他喜欢大谈判断力，但如果你90%以上的时候都觉得布什是对的，那你的判断力如何也不言自明了。

奥巴马以立意高远著称，他那些最令人难忘的演讲也体现了这一点，他接受提名的演说在内容和结构方面都显得比通常更有条理。他以介绍自己的父母为开场，然后很快就转向对自己施政纲领的平淡叙述。这次演讲严重倾向于经济政策，奥巴马提及了修改税法，并强调了当前的信贷危机和高油价造成的问题。

奥巴马说，我们用以衡量经济实力的基本标准是，我们是否兑现了基本的承诺，正是这一承诺令我们的国家变得伟大，这一承诺也是我今晚站在这里的唯一理由。

奥巴马演讲的很大一部分内容是关于油价和全球变暖的威胁，并再次谈到了能源独立的竞选政策。奥巴马简单地描绘了该政策：政府将在替代能源上投入1,500亿美元，并新增500万个工作机会。他再次指责麦凯恩身为参议员，却在美国能源依赖性越来越强的时候消极旁观。

众多奥巴马的支持者挤在足球场听他演讲

奥巴马说，过去30年里，华盛顿一直在讨论我们依赖石油的问题，而麦凯恩担任参议员已有26年。现在，我们进口的石油数量是麦凯恩当选参议员之时的三倍。

奥巴马还重点强调他适合担任三军统帅，并指出共和党人未能确保国家安全。他誓言结束伊拉克战争，并承诺不会挑起不必要的冲突。他说，作为三军总司令，我在保卫国家方面绝不会犹豫，但只有在明确使命的情况下，我才会让我们的军队去承受危险，并且庄严承诺为他们提供战斗所需的装备，以及他们归国后所应得的关照和福利。