David Kusnet was chief speechwriter for former President Bill Clinton from 1992 through 1994. He is the author of Love the Work, Hate the Job: Why America's Best Workers Are Unhappier than Ever.

Barack Obama's acceptance speech continued the shift in the campaign's message--started by Joe Biden last night--from the uplifting "change you can believe in" to the more down-to-earth "the change we need."

As he begins the general election campaign, Obama has three reasons to be down-to-earth. First, to demonstrate that he offers more than glittering generalities. Second, to appeal to the working class voters who will decide this election. And, third, because it's going to be a street fight against experienced Republican message-meisters who have mauled Democratic candidates from Walter Mondale and Michael Dukakis to Al Gore and John Kerry.

Yes, Obama was as eloquent as ever last night. His speech featured what most acceptance speeches don't: a consistent theme, from start to finish. Obama attributed his success-- indeed, his birth--to "America's promise," which every generation has defended and extended. Now, it's up to today's Americans to carry the promise forward into the new century by creating "the change we need." John McCain is a good man, but he's too tied to President Bush--and, by implication, too tired and old--to get the job done. See, you can sum it all up in 60 seconds--the sign of a great speech.

In its method, if not its message, it recalled Ronald Reagan.The Great Communicator would begin his speeches by describing what this country stands for. Then he'd explain why his ideas advanced American ideals, while his rivals' records and programs violated those values. Often, Reagan would find common ground with the rank-and-file members of the other party, while regretting that their current leaders were betraying their trust.

Thursday night, Obama used much the same technique. After attributing his rise to America's promise--aim high, work hard, and reap your reward--Obama explained that the dream has been endangered during Bush's presidency. But, instead of simply bemoaning failed policies and economic problems, Obama kept contrasting them to America's inherent goodness. He began his critique, "America, we are better than the last eight years." And then he constructed an original and effective litany, introducing every problem with the declaration that "this country is more decent than" the social injustice that he went on to describe.

In another masterful exercise of rhetorical ju-jitsu, he presented prominent Republicans as those who look down on regular Americans. Referring to former senator and McCain economic adviser Phil Gram's gaffe that economically anxious Americans have become "a nation of whiners," Obama defended the guts and grit of workers, soldiers, and small business people whom he has met.

While Obama has often delivered programmatic speeches, this was the first time he said, simply, "Let me spell out exactly what that change would mean if I am president." For the next few minutes, sounding like a president delivering a State of the Union Address, Obama offered a detailed domestic program, from middle class tax cuts to alternative energy sources and investments in public education and college opportunity.

If that is "the change we need," then why couldn't McCain provide it, too? Here, Obama pursued the most effective line of attack against an aging war hero. It's not that McCain "doesn't care" about his fellow citizens' problems--it's that he "doesn't know" about them or, more bluntly, "doesn't get it." This line of attack allows listeners to draw their own conclusions. Is McCain too insulated by wealth? Too bound by ideology? Too incurious? Too much a part of the past? Or all of the above?

Conservative commentators are already calling Obama's speech too harsh or even angry. But its tone and structure closely resemble Ronald Reagan's acceptance speech in 1980, much of which attacked the unpopular incumbent, Jimmy Carter, for falling far short of America's greatness. At one point, Reagan asked: "Can anyone look at the record of this administration and say, ‘Well done?' Can anyone compare the state of our economy when the Carter Administration took office with where we are today and say, ‘Keep up the good work?' Can anyone look at our reduced standing in the world today and say, ‘Let's have four more years of this?'" The Gipper answered himself: "I believe the American people are going to answer these questions the first week of November and their answer will be, ‘No--we've had enough.'"

As he often does, Obama saved the poetry--the recollection of the Reverend Martin Luther King, Jr., who delivered his "I Have a Dream" speech exactly 45 years earlier--for the conclusion of his remarks. Obama can still soar to loftier heights than any other public figure today. But, Thursday night, the former community organizer showed he's also ready to take it to the streets.

--David Kusnet