CHARLOTTE, N.C. -- The man who ran on hope and change didn't walk away from them. He redefined them for the long haul.
And a president who has been accused of being a collectivist and a socialist didn't abandon a vision of shared burdens and purposes. He replied forcefully with a call for a renewal of citizenship, "the idea that this country only works when we accept certain obligations to one another, and to future generations."
"We, the people, recognize that we have responsibilities as well as rights," he declared, "that our destinies are bound together; that a freedom which only asks what's in it for me, a freedom without a commitment to others, a freedom without love or charity or duty or patriotism, is unworthy of our founding ideals, and those who died in their defense."
Rarely has an American election provided such a sharp clash of philosophies. When President Obama told a fired-up Democratic convention crowd that the contest will involve "the clearest choice of any time in a generation," and "a choice between two fundamentally different visions for the future," he was not exaggerating. He took the Republicans' new radical individualism head on.
Obama's was a speech aimed less at shaking up the campaign than at building on an existing narrative. The president did not defend his economic record. He left that to Bill Clinton. He did not even promise rapid recovery.
On the contrary, he told voters: "I won't pretend the path I'm offering is quick or easy."
Indeed, he seemed to reach back to John F. Kennedy's summons that Americans first ask what they could do for the country. "As citizens," Obama said, "we understand that America is not about what can be done for us. It's about what can be done by us, together, through the hard and frustrating but necessary work of self-government."
And thus his redefinition of hope and change. Faced with assertions that he can no longer inspire the elation he called forth four years ago, Obama challenged those who had supported him to stay in the fight for the longer term and do the work required to get where they originally wanted to go.
"If you turn away now -- if you buy into the cynicism that the change we fought for isn't possible, well, change will not happen," the president said. "If you give up on the idea that your voice can make a difference, then other voices will fill the void: lobbyists and special interests; the people with the $10 million checks who are trying to buy this election and those who are trying to make it harder for you to vote."
Of course, this is an election, not a philosophical exercise, so Obama was concrete about his differences with Mitt Romney and the Republicans' quest for a spare government that would ask even less of the already successful.
He criticized his foes on Medicare and Social Security, on their refusal to accept any deficit plans that included higher taxes on the wealthy, on education spending and tuition aid.
"Over and over, we have been told by our opponents that bigger tax cuts and fewer regulations are the only way; that since government can't do everything, it should do almost nothing," he said. "If you can't afford health insurance, hope that you don't get sick. If a company releases toxic pollution into the air your children breathe, well, that's the price of progress."
And he mocked the GOP's diagnosis of more tax cuts in all economic circumstances: "Feel a cold coming on? Take two tax cuts, roll back some regulations, and call us in the morning!"
In sketching an itinerary for "moving forward," Obama spoke more of goals than of policies, highlighting an expansion of manufacturing, energy independence, education and job training, and climate change, an issue that has largely been absent from the public discussion since 2010.
Politicians usually run campaigns based on what they will do, or have done, for voters. Obama will certainly do his share of this, and did some of it Thursday.
Yet his heart seems not to lie in transactional politics. He prefers challenges to promises, obligations to privileges, reason to emotion.
"The path we offer may be harder," he said, "but it leads to a better place."
This is not a typical campaign pledge. It implies neither ease nor comfort but burdens worth bearing and responsibilities worth shouldering. It is still a form of hope, but one that requires far more than going to rallies and cheering.