"And the truth is, it will take more than a few years for us to solve challenges that have built up over decades," he added. "It will require common effort, shared responsibility and the kind of bold, persistent experimentation that Franklin Roosevelt pursued during the only crisis worse than this one."
Strolling out to a warm embrace from his wife, Michelle, and U2's "City of Blinding Lights" in a conscious nod to the spirit of '08, Obama fired up the packed crowd even as his speech once again summoned his law-professorial side, with flashes of humor.
In a sign, arguably, of how much politics has changed since the time of FDR, Obama told the nation that the only thing we have to fear . . . is a return to Republican rule.
On a litany of key policy issues, he attempted to outline major differences between the two parties, and to portray the Democrats as the ones who will offer "a better path" to treat global warming seriously, finance alternative energy, retrain idled factory workers and recruit 100,000 new math and science teachers.
"And yes, my plan will continue to reduce the carbon pollution that is heating our planet - because climate change is not a hoax," he said. "More droughts and floods and wildfires are not a joke. They're a threat to our children's future. And in this election, you can do something about it."
But he did seize one advantage of incumbency, needling his GOP fall opponent Mitt Romney's lack of foreign-policy experience. "You might not be ready for diplomacy with Beijing if you can't visit the Olympics without insulting our closest ally," the president said.
Experts agreed the main pressure on the president Thursday was to lay out a bold and appealing - but not too wonkish or detail-oriented - vision for a second term. The ball was teed up during Wednesday's stem-winder from the 42nd president, Bill Clinton, who defended the 44th president's policies - from the auto-industry rescue to health-care reform - and laid out his first-term obstacles in a way that Obama himself never could.
"Clinton is a communicator, while Obama is an orator - there's a difference," said G. Terry Madonna, the Franklin & Marshall College political scientist and pollster, who attended the Charlotte confab. He said the direction of a potential Obama second term is "the big unanswered question" that caused viewers to check in.
The president's speech came after two busy weeks that nonetheless seemed to confirm the status of political conventions as something of a 20th-century relic. Even with both parties downsizing to just three days from the traditional four and scaled-back network coverage, the confabs struggled for viewers against NFL football, MTV's Video Music Awards and a reality show called "Here Comes Honey Boo Boo."
Millions did watch, but it was largely preaching to the choir. Democratic attendees and TV viewers were electrified by the likes of Clinton and the first lady, but conservatives watching on Fox News or reading the Drudge Report mainly know that some delegates booed a platform change that added the word "God." Obama's appeal Thursday night to undecided voters was the ultimate example of narrowcasting.
"If you reject the notion that this nation's promise is reserved for the few, your voice must be heard in this election," Obama said. "If you reject the notion that our government is forever beholden to the highest bidder, you need to stand up in this election."
In the end, the words that Obama spoke at 10 p.m. Thursday may not have as much impact as a number that comes out at 8:30 a.m. Friday: the unemployment rate.
Or as Clinton calls it: arithmetic.
Contact Will Bunch at email@example.com or 215-854-2957. Follow him on Twitter @Will_Bunch. Read his blog at Attytood.com.